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Wikipedia

SQL

This article is about the database language. For the IATA code, see San Carlos Airport (California).
"SEQUEL" redirects here. For the topic of the word, see sequel. For other uses, see sequel (disambiguation).

SQL (() S-Q-L, "sequel"; Structured Query Language) is a domain-specific language used in programming and designed for managing data held in a relational database management system (RDBMS), or for stream processing in a relational data stream management system (RDSMS). It is particularly useful in handling structured data, i.e. data incorporating relations among entities and variables.

SQL (file format)
Filename extension
.sql
Internet media type
application/sql
Developed byISO/IEC
Initial release1986 (1986)
Type of formatDatabase
StandardISO/IEC 9075
Open format?Yes
Websitewww.iso.org/standard/63555.html

SQL offers two main advantages over older read–write APIs such as ISAM or VSAM. Firstly, it introduced the concept of accessing many records with one single command. Secondly, it eliminates the need to specify how to reach a record, e.g. with or without an index.

Originally based upon relational algebra and tuple relational calculus, SQL consists of many types of statements, which may be informally classed as sublanguages, commonly: a data query language (DQL), a data definition language (DDL), a data control language (DCL), and a data manipulation language (DML). The scope of SQL includes data query, data manipulation (insert, update and delete), data definition (schema creation and modification), and data access control. Although SQL is essentially a declarative language (4GL), it also includes procedural elements.

SQL was one of the first commercial languages to use Edgar F. Codd’s relational model. The model was described in his influential 1970 paper, "A Relational Model of Data for Large Shared Data Banks". Despite not entirely adhering to the relational model as described by Codd, it became the most widely used database language.

SQL became a standard of the American National Standards Institute (ANSI) in 1986, and of the International Organization for Standardization (ISO) in 1987. Since then, the standard has been revised to include a larger set of features. Despite the existence of standards, most SQL code requires at least some changes before being ported to different database systems.

Contents

SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce after learning about the relational model from Edgar F. Codd in the early 1970s. This version, initially called SEQUEL (Structured English Query Language), was designed to manipulate and retrieve data stored in IBM's original quasirelational database management system, System R, which a group at IBM San Jose Research Laboratory had developed during the 1970s.

Chamberlin and Boyce's first attempt at a relational database language was SQUARE (Specifying QUeries in A Relational Environment), but it was difficult to use due to subscript/superscript notation. After moving to the San Jose Research Laboratory in 1973, they began work on a sequel to SQUARE. The name SEQUEL was later changed to SQL (dropping the vowels) because "SEQUEL" was a trademark of the UK-based Hawker Siddeley Dynamics Engineering Limited company. The label Structured Query Language later became the acronym for SQL.

After testing SQL at customer test sites to determine the usefulness and practicality of the system, IBM began developing commercial products based on their System R prototype, including System/38, SQL/DS, and DB2, which were commercially available in 1979, 1981, and 1983, respectively.

In the late 1970s, Relational Software, Inc. (now Oracle Corporation) saw the potential of the concepts described by Codd, Chamberlin, and Boyce, and developed their own SQL-based RDBMS with aspirations of selling it to the U.S. Navy, Central Intelligence Agency, and other U.S. government agencies. In June 1979, Relational Software introduced the first commercially available implementation of SQL, Oracle V2 (Version2) for VAX computers.

By 1986, ANSI and ISO standard groups officially adopted the standard "Database Language SQL" language definition. New versions of the standard were published in 1989, 1992, 1996, 1999, 2003, 2006, 2008, 2011, and most recently, 2016.

Main article: SQL syntax
U P D A T E c l a u s e { U P D A T E c o u n t r y S E T c l a u s e { S E T p o p u l a t i o n = p o p u l a t i o n + 1 e x p r e s s i o n W H E R E c l a u s e { W H E R E n a m e = U S A e x p r e s s i o n p r e d i c a t e ; } statement {\displaystyle \left.{\begin{array}{rl}\textstyle {\mathtt {UPDATE~clause}}&\{{\mathtt {UPDATE\ country}}\\\textstyle {\mathtt {SET~clause}}&\{{\mathtt {SET\ population=~}}\overbrace {\mathtt {population+1}} ^{\mathtt {expression}}\\\textstyle {\mathtt {WHERE~clause}}&\{{\mathtt {WHERE\ \underbrace {{name=}\overbrace {'USA'} ^{expression}} _{predicate};}}\end{array}}\right\}{\textstyle {\texttt {statement}}}}
A chart showing several of the SQL language elements that compose a single statement

The SQL language is subdivided into several language elements, including:

  • Clauses, which are constituent components of statements and queries. (In some cases, these are optional.)
  • Expressions, which can produce either scalar values, or tables consisting of columns and rows of data
  • Predicates, which specify conditions that can be evaluated to SQL three-valued logic (3VL) (true/false/unknown) or Boolean truth values and are used to limit the effects of statements and queries, or to change program flow.
  • Queries, which retrieve the data based on specific criteria. This is an important element of SQL.
  • Statements, which may have a persistent effect on schemata and data, or may control transactions, program flow, connections, sessions, or diagnostics.
    • SQL statements also include the semicolon (";") statement terminator. Though not required on every platform, it is defined as a standard part of the SQL grammar.
  • Insignificant whitespace is generally ignored in SQL statements and queries, making it easier to format SQL code for readability.

SQL is designed for a specific purpose: to query data contained in a relational database. SQL is a set-based, declarative programming language, not an imperative programming language like C or BASIC. However, extensions to Standard SQL add procedural programming language functionality, such as control-of-flow constructs. These include:

Source Abbreviation Full name
ANSI/ISO Standard SQL/PSM SQL/Persistent Stored Modules
Interbase / Firebird PSQL Procedural SQL
IBM DB2 SQL PL SQL Procedural Language (implements SQL/PSM)
IBM Informix SPL Stored Procedural Language
IBM Netezza NZPLSQL (based on Postgres PL/pgSQL)
Invantive PSQL Invantive Procedural SQL (implements SQL/PSM and PL/SQL)
MariaDB SQL/PSM, PL/SQL SQL/Persistent Stored Module (implements SQL/PSM), Procedural Language/SQL (based on Ada)
Microsoft / Sybase T-SQL Transact-SQL
Mimer SQL SQL/PSM SQL/Persistent Stored Module (implements SQL/PSM)
MySQL SQL/PSM SQL/Persistent Stored Module (implements SQL/PSM)
MonetDB SQL/PSM SQL/Persistent Stored Module (implements SQL/PSM)
NuoDB SSP Starkey Stored Procedures
Oracle PL/SQL Procedural Language/SQL (based on Ada)
PostgreSQL PL/pgSQL Procedural Language/PostgreSQL Structured Query Language (based on reduced PL/SQL)
SAP R/3 ABAP Advanced Business Application Programming
SAP HANA SQLScript SQLScript
Sybase Watcom-SQL SQL Anywhere Watcom-SQL Dialect
Teradata SPL Stored Procedural Language

In addition to the standard SQL/PSM extensions and proprietary SQL extensions, procedural and object-oriented programmability is available on many SQL platforms via DBMS integration with other languages. The SQL standard defines SQL/JRT extensions (SQL Routines and Types for the Java Programming Language) to support Java code in SQL databases. Microsoft SQL Server 2005 uses the SQLCLR (SQL Server Common Language Runtime) to host managed .NET assemblies in the database, while prior versions of SQL Server were restricted to unmanaged extended stored procedures primarily written in C. PostgreSQL lets users write functions in a wide variety of languages—including Perl, Python, Tcl, JavaScript (PL/V8) and C.

Overview

SQL implementations are incompatible between vendors and do not necessarily completely follow standards. In particular, date and time syntax, string concatenation, NULLs, and comparison case sensitivity vary from vendor to vendor. Particular exceptions are PostgreSQL and Mimer SQL which strive for standards compliance, though PostgreSQL does not adhere to the standard in all cases. For example, the folding of unquoted names to lower case in PostgreSQL is incompatible with the SQL standard, which says that unquoted names should be folded to upper case. Thus, Foo should be equivalent to FOO not foo according to the standard.

Popular implementations of SQL commonly omit support for basic features of Standard SQL, such as the DATE or TIME data types. The most obvious such examples, and incidentally the most popular commercial and proprietary SQL DBMSs, are Oracle (whose DATE behaves as DATETIME, and lacks a TIME type) and MS SQL Server (before the 2008 version). As a result, SQL code can rarely be ported between database systems without modifications.

Reasons for incompatibility

Several reasons for this lack of portability between database systems include:

  • The complexity and size of the SQL standard means that most implementers do not support the entire standard.
  • The standard does not specify database behavior in several important areas (e.g. indices, file storage...), leaving implementations to decide how to behave.
  • The SQL standard precisely specifies the syntax that a conforming database system must implement. However, the standard's specification of the semantics of language constructs is less well-defined, leading to ambiguity.
  • Many database vendors have large existing customer bases; where the newer version of the SQL standard conflicts with the prior behavior of the vendor's database, the vendor may be unwilling to break backward compatibility.
  • Little commercial incentive exists for vendors to make changing database suppliers easier (see vendor lock-in).
  • Users evaluating database software tend to place other factors such as performance higher in their priorities than standards conformance.

Standardization history

SQL was adopted as a standard by the ANSI in 1986 as SQL-86 and the ISO in 1987. It is maintained by ISO/IEC JTC 1, Information technology, Subcommittee SC 32, Data management and interchange.

Until 1996, the National Institute of Standards and Technology (NIST) data-management standards program certified SQL DBMS compliance with the SQL standard. Vendors now self-certify the compliance of their products.

The original standard declared that the official pronunciation for "SQL" was an initialism: ("ess cue el"). Regardless, many English-speaking database professionals (including Donald Chamberlin himself) use the acronym-like pronunciation of ("sequel"), mirroring the language's prerelease development name, "SEQUEL".
The SQL standard has gone through a number of revisions:

Year Name Alias Comments
1986 SQL-86 SQL-87 First formalized by ANSI
1989 SQL-89 FIPS 127-1 Minor revision that added integrity constraints, adopted as FIPS 127-1
1992 SQL-92 SQL2, FIPS 127-2 Major revision (ISO 9075), Entry Level SQL-92 adopted as FIPS 127-2
1999 SQL:1999 SQL3 Added regular expression matching, recursive queries (e.g. transitive closure), triggers, support for procedural and control-of-flow statements, nonscalar types (arrays), and some object-oriented features (e.g. structured types), support for embedding SQL in Java (SQL/OLB) and vice versa (SQL/JRT)
2003 SQL:2003 Introduced XML-related features (SQL/XML), window functions, standardized sequences, and columns with autogenerated values (including identity columns)
2006 SQL:2006 ISO/IEC 9075-14:2006 defines ways that SQL can be used with XML. It defines ways of importing and storing XML data in an SQL database, manipulating it within the database, and publishing both XML and conventional SQL-data in XML form. In addition, it lets applications integrate queries into their SQL code with XQuery, the XML Query Language published by the World Wide Web Consortium (W3C), to concurrently access ordinary SQL-data and XML documents.
2008 SQL:2008 Legalizes ORDER BY outside cursor definitions. Adds INSTEAD OF triggers, TRUNCATE statement, FETCH clause
2011 SQL:2011 Adds temporal data (PERIOD FOR) (more information at: Temporal database#History). Enhancements for window functions and FETCH clause.
2016 SQL:2016 Adds row pattern matching, polymorphic table functions, JSON
2019 SQL:2019 Adds Part 15, multidimensional arrays (MDarray type and operators)

Current standard

The standard is commonly denoted by the pattern: ISO/IEC 9075-n:yyyy Part n: title, or, as a shortcut, ISO/IEC 9075.

ISO/IEC 9075 is complemented by ISO/IEC 13249: SQL Multimedia and Application Packages (SQL/MM), which defines SQL-based interfaces and packages to widely spread applications such as video, audio, and spatial data. Interested parties may purchase SQL standards documents from ISO, IEC or ANSI. A draft of SQL:2008 is freely available as a zip archive.

Anatomy of SQL Standard

The SQL standard is divided into 10 parts, but with gaps in the numbering due to the withdrawal of outdated parts.

  • ISO/IEC 9075-1:2016 Part 1: Framework (SQL/Framework). It provides logical concepts.
  • ISO/IEC 9075-2:2016 Part 2: Foundation (SQL/Foundation). It contains the most central elements of the language and consists of both mandatory and optional features.
  • ISO/IEC 9075-3:2016 Part 3: Call-Level Interface (SQL/CLI). It defines interfacing components (structures, procedures, variable bindings) that can be used to execute SQL statements from applications written in Ada, C respectively C++, COBOL, Fortran, MUMPS, Pascal or PL/I. (For Java see part 10.) SQL/CLI is defined in such a way that SQL statements and SQL/CLI procedure calls are treated as separate from the calling application's source code. Open Database Connectivity is a well-known superset of SQL/CLI. This part of the standard consists solely of mandatory features.
  • ISO/IEC 9075-4:2016 Part 4: Persistent stored modules (SQL/PSM). It standardizes procedural extensions for SQL, including flow of control, condition handling, statement condition signals and resignals, cursors and local variables, and assignment of expressions to variables and parameters. In addition, SQL/PSM formalizes declaration and maintenance of persistent database language routines (e.g., "stored procedures"). This part of the standard consists solely of optional features.
  • ISO/IEC 9075-9:2016 Part 9: Management of External Data (SQL/MED). It provides extensions to SQL that define foreign-data wrappers and datalink types to allow SQL to manage external data. External data is data that is accessible to, but not managed by, an SQL-based DBMS. This part of the standard consists solely of optional features.
  • ISO/IEC 9075-10:2016 Part 10: Object language bindings (SQL/OLB). It defines the syntax and semantics of SQLJ, which is SQL embedded in Java (see also part 3). The standard also describes mechanisms to ensure binary portability of SQLJ applications, and specifies various Java packages and their contained classes. This part of the standard consists solely of optional features. Unlike SQL/OLB JDBC defines an API and is not part of the SQL standard.[citation needed]
  • ISO/IEC 9075-11:2016 Part 11: Information and definition schemas (SQL/Schemata). It defines the Information Schema and Definition Schema, providing a common set of tools to make SQL databases and objects self-describing. These tools include the SQL object identifier, structure and integrity constraints, security and authorization specifications, features and packages of ISO/IEC 9075, support of features provided by SQL-based DBMS implementations, SQL-based DBMS implementation information and sizing items, and the values supported by the DBMS implementations. This part of the standard contains both mandatory and optional features.
  • ISO/IEC 9075-13:2016 Part 13: SQL Routines and types using the Java TM programming language (SQL/JRT). It specifies the ability to invoke static Java methods as routines from within SQL applications ('Java-in-the-database'). It also calls for the ability to use Java classes as SQL structured user-defined types. This part of the standard consists solely of optional features.
  • ISO/IEC 9075-14:2016 Part 14: XML-Related Specifications (SQL/XML). It specifies SQL-based extensions for using XML in conjunction with SQL. The XML data type is introduced, as well as several routines, functions, and XML-to-SQL data type mappings to support manipulation and storage of XML in an SQL database. This part of the standard consists solely of optional features.[citation needed]
  • ISO/IEC 9075-15:2019 Part 15: Multi-dimensional arrays (SQL/MDA). It specifies a multidimensional array type (MDarray) for SQL, along with operations on MDarrays, MDarray slices, MDarray cells, and related features. This part of the standard consists solely of optional features.

Extensions to the ISO/IEC Standard

ISO/IEC 9075 is complemented by ISO/IEC 13249 SQL Multimedia and Application Packages. This closely related but separate standard is developed by the same committee. It defines interfaces and packages based on SQL. The aim is a unified access to typical database applications like text, pictures, data mining or spatial data.

  • ISO/IEC 13249-1:2016 Part 1: Framework
  • ISO/IEC 13249-2:2003 Part 2: Full-Text
  • ISO/IEC 13249-3:2016 Part 3: Spatial
  • ISO/IEC 13249-5:2003 Part 5: Still image
  • ISO/IEC 13249-6:2006 Part 6: Data mining
  • ISO/IEC 13249-7:2013 Part 7: History
  • ISO/IEC 13249-8:xxxx Part 8: Metadata Registry Access MRA (work in progress)

Technical reports

ISO/IEC 9075 is also accompanied by a series of Technical Reports, published as ISO/IEC TR 19075. These Technical Reports explain the justification for and usage of some features of SQL, giving examples where appropriate. The Technical Reports are non-normative; if there is any discrepancy from 9075, the text in 9075 holds. Currently available 19075 Technical Reports are:

  • ISO/IEC TR 19075-1:2011 Part 1: XQuery Regular Expression Support in SQL
  • ISO/IEC TR 19075-2:2015 Part 2: SQL Support for Time-Related Information
  • ISO/IEC TR 19075-3:2015 Part 3: SQL Embedded in Programs using the Java programming language
  • ISO/IEC TR 19075-4:2015 Part 4: SQL with Routines and types using the Java programming language
  • ISO/IEC TR 19075-5:2016 Part 5: Row Pattern Recognition in SQL
  • ISO/IEC TR 19075-6:2017 Part 6: SQL support for JavaScript Object Notation (JSON)
  • ISO/IEC TR 19075-7:2017 Part 7: Polymorphic table functions in SQL
  • ISO/IEC TR 19075-8:2019 Part 8: Multi-Dimensional Arrays (SQL/MDA)
  • ISO/IEC TR 19075-9:2020 Part 9: Online analytic processing (OLAP) capabilities

A distinction should be made between alternatives to SQL as a language, and alternatives to the relational model itself. Below are proposed relational alternatives to the SQL language. See navigational database and NoSQL for alternatives to the relational model.

Distributed Relational Database Architecture (DRDA) was designed by a work group within IBM from 1988 to 1994. DRDA enables network connected relational databases to cooperate to fulfill SQL requests.

An interactive user or program can issue SQL statements to a local RDB and receive tables of data and status indicators in reply from remote RDBs. SQL statements can also be compiled and stored in remote RDBs as packages and then invoked by package name. This is important for the efficient operation of application programs that issue complex, high-frequency queries. It is especially important when the tables to be accessed are located in remote systems.

The messages, protocols, and structural components of DRDA are defined by the Distributed Data Management Architecture. Distributed SQL processing ala DRDA is distinctive from contemporary distributed SQL databases.

Design

SQL deviates in several ways from its theoretical foundation, the relational model and its tuple calculus. In that model, a table is a set of tuples, while in SQL, tables and query results are lists of rows; the same row may occur multiple times, and the order of rows can be employed in queries (e.g. in the LIMIT clause). Critics argue that SQL should be replaced with a language that returns strictly to the original foundation: for example, see The Third Manifesto.

Orthogonality and completeness

Early specifications did not support major features, such as primary keys. Result sets could not be named, and subqueries had not been defined. These were added in 1992.

The lack of sum types have been described as a roadblock to full use of SQL's user-defined types. JSON support, for example, needs to be added by a new standard in 2016.

Null

The concept of Null is the subject of some debates. The Null marker indicates the absence of a value, and is distinct from a value of 0 for an integer column or an empty string for a text column. The concept of Nulls enforces the 3-valued-logic in SQL, which is a concrete implementation of the general 3-valued logic.

Duplicates

Another popular criticism is that it allows duplicate rows, making integration with languages such as Python, whose data types might make accurately representing the data difficult, in terms of parsing and by the absence of modularity.

This is usually avoided by declaring a primary key, or a unique constraint, with one or more columns that uniquely identifies a row in the table.

Impedance mismatch

In a similar sense to object–relational impedance mismatch, a mismatch occurs between the declarative SQL language and the procedural languages in which SQL is typically embedded.

The SQL standard defines three kinds of data types:[citation needed]

  • predefined data types
  • constructed types
  • user-defined types.

Constructed types are one of ARRAY, MULTISET, REF(erence), or ROW. User-defined types are comparable to classes in object-oriented language with their own constructors, observers, mutators, methods, inheritance, overloading, overwriting, interfaces, and so on. Predefined data types are intrinsically supported by the implementation.

Predefined data types

  • Character types
  • Character (CHAR)
  • Character varying (VARCHAR)
  • Character large object (CLOB)
  • National character types
  • National character (NCHAR)
  • National character varying (NCHAR VARYING)
  • National character large object (NCLOB)
  • Binary types
  • Binary (BINARY)
  • Binary varying (VARBINARY)
  • Binary large object (BLOB)
  • Numeric types
  • Exact numeric types (NUMERIC, DECIMAL, SMALLINT, INTEGER, BIGINT)
  • Approximate numeric types (FLOAT, REAL, DOUBLE PRECISION)
  • Decimal floating-point type (DECFLOAT)
  • Datetime types (DATE, TIME, TIMESTAMP)
  • Interval type (INTERVAL)
  • Boolean
  • XML
  • JSON
  1. Formally, "SQL-data" statements excluding "SQL-data change" statements; this is primarily the Select statement.
  2. Formally, "SQL-schema" statements.
  3. Formally, "SQL-data change" statements
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SQL standards documents

ITTF publicly available standards and technical reports

The ISO/IEC Information Technology Task Force publishes publicly available standards including SQL. Technical Corrigenda (corrections) and Technical Reports (discussion documents) are published there.

SQL -- Part 1: Framework (SQL/Framework)

Draft documents

Formal SQL standards are available from ISO and ANSI for a fee. For informative use, as opposed to strict standards compliance, late drafts often suffice.

SQLat Wikipedia's sister projects

SQL
SQL Language Watch Edit This article is about the database language For the IATA code see San Carlos Airport California SEQUEL redirects here For the topic of the word see sequel For other uses see sequel disambiguation SQL ˌ ɛ s ˌ k juː ˈ ɛ l listen S Q L 4 ˈ s iː k w el sequel Structured Query Language 5 is a domain specific language used in programming and designed for managing data held in a relational database management system RDBMS or for stream processing in a relational data stream management system RDSMS It is particularly useful in handling structured data i e data incorporating relations among entities and variables SQL Structured Query Language ParadigmDeclarativeFamilyQuery languageDesigned byDonald D Chamberlin Raymond F BoyceDeveloperISO IECFirst appeared1974 47 years ago 1974 Stable releaseSQL 2016 December 2016 4 years ago 2016 12 Typing disciplineStatic strongOSCross platformWebsitewww wbr iso wbr org wbr standard wbr 63555 wbr htmlMajor implementationsManyDialectsSQL 86 SQL 89 SQL 92 SQL 1999 SQL 2003 SQL 2006 SQL 2008 SQL 2011 SQL 2016Influenced byDatalogInfluencedCQL LINQ SPARQL SOQL PowerShell 1 JPQL jOOQ N1QLStructured Query Language at WikibooksSQL file format Filename extension sqlInternet media typeapplication sql 2 3 Developed byISO IECInitial release1986 1986 Type of formatDatabaseStandardISO IEC 9075Open format YesWebsitewww wbr iso wbr org wbr standard wbr 63555 wbr html SQL offers two main advantages over older read write APIs such as ISAM or VSAM Firstly it introduced the concept of accessing many records with one single command Secondly it eliminates the need to specify how to reach a record e g with or without an index Originally based upon relational algebra and tuple relational calculus SQL consists of many types of statements 6 which may be informally classed as sublanguages commonly a data query language DQL a a data definition language DDL b a data control language DCL and a data manipulation language DML c 7 The scope of SQL includes data query data manipulation insert update and delete data definition schema creation and modification and data access control Although SQL is essentially a declarative language 4GL it also includes procedural elements SQL was one of the first commercial languages to use Edgar F Codd s relational model The model was described in his influential 1970 paper A Relational Model of Data for Large Shared Data Banks 8 Despite not entirely adhering to the relational model as described by Codd it became the most widely used database language 9 10 SQL became a standard of the American National Standards Institute ANSI in 1986 and of the International Organization for Standardization ISO in 1987 11 Since then the standard has been revised to include a larger set of features Despite the existence of standards most SQL code requires at least some changes before being ported to different database systems Contents 1 History 2 Syntax 3 Procedural extensions 4 Interoperability and standardization 4 1 Overview 4 2 Reasons for incompatibility 4 3 Standardization history 4 4 Current standard 4 4 1 Anatomy of SQL Standard 4 4 2 Extensions to the ISO IEC Standard 4 4 3 Technical reports 5 Alternatives 6 Distributed SQL processing 7 Criticisms 7 1 Design 7 2 Orthogonality and completeness 7 3 Null 7 4 Duplicates 7 5 Impedance mismatch 8 SQL data types 8 1 Predefined data types 9 See also 10 Notes 11 References 12 Sources 12 1 SQL standards documents 12 1 1 ITTF publicly available standards and technical reports 12 1 2 Draft documents 13 External linksHistory EditSQL was initially developed at IBM by Donald D Chamberlin and Raymond F Boyce after learning about the relational model from Edgar F Codd 12 in the early 1970s 13 This version initially called SEQUEL Structured English Query Language was designed to manipulate and retrieve data stored in IBM s original quasirelational database management system System R which a group at IBM San Jose Research Laboratory had developed during the 1970s 13 Chamberlin and Boyce s first attempt at a relational database language was SQUARE Specifying QUeries in A Relational Environment but it was difficult to use due to subscript superscript notation After moving to the San Jose Research Laboratory in 1973 they began work on a sequel to SQUARE 12 The name SEQUEL was later changed to SQL dropping the vowels because SEQUEL was a trademark of the UK based Hawker Siddeley Dynamics Engineering Limited company 14 The label Structured Query Language later became the acronym for SQL After testing SQL at customer test sites to determine the usefulness and practicality of the system IBM began developing commercial products based on their System R prototype including System 38 SQL DS and DB2 which were commercially available in 1979 1981 and 1983 respectively 15 In the late 1970s Relational Software Inc now Oracle Corporation saw the potential of the concepts described by Codd Chamberlin and Boyce and developed their own SQL based RDBMS with aspirations of selling it to the U S Navy Central Intelligence Agency and other U S government agencies In June 1979 Relational Software introduced the first commercially available implementation of SQL Oracle V2 Version2 for VAX computers By 1986 ANSI and ISO standard groups officially adopted the standard Database Language SQL language definition New versions of the standard were published in 1989 1992 1996 1999 2003 2006 2008 2011 12 and most recently 2016 16 Syntax EditMain article SQL syntax U P D A T E c l a u s e U P D A T E c o u n t r y S E T c l a u s e S E T p o p u l a t i o n p o p u l a t i o n 1 e x p r e s s i o n W H E R E c l a u s e W H E R E n a m e U S A e x p r e s s i o n p r e d i c a t e statement displaystyle left begin array rl textstyle mathtt UPDATE clause amp mathtt UPDATE country textstyle mathtt SET clause amp mathtt SET population overbrace mathtt population 1 mathtt expression textstyle mathtt WHERE clause amp mathtt WHERE underbrace name overbrace USA expression predicate end array right textstyle texttt statement A chart showing several of the SQL language elements that compose a single statement The SQL language is subdivided into several language elements including Clauses which are constituent components of statements and queries In some cases these are optional 17 Expressions which can produce either scalar values or tables consisting of columns and rows of data Predicates which specify conditions that can be evaluated to SQL three valued logic 3VL true false unknown or Boolean truth values and are used to limit the effects of statements and queries or to change program flow Queries which retrieve the data based on specific criteria This is an important element of SQL Statements which may have a persistent effect on schemata and data or may control transactions program flow connections sessions or diagnostics SQL statements also include the semicolon statement terminator Though not required on every platform it is defined as a standard part of the SQL grammar Insignificant whitespace is generally ignored in SQL statements and queries making it easier to format SQL code for readability Procedural extensions EditSQL is designed for a specific purpose to query data contained in a relational database SQL is a set based declarative programming language not an imperative programming language like C or BASIC However extensions to Standard SQL add procedural programming language functionality such as control of flow constructs These include Source Abbreviation Full nameANSI ISO Standard SQL PSM SQL Persistent Stored ModulesInterbase Firebird PSQL Procedural SQLIBM DB2 SQL PL SQL Procedural Language implements SQL PSM IBM Informix SPL Stored Procedural LanguageIBM Netezza NZPLSQL 18 based on Postgres PL pgSQL Invantive PSQL 19 Invantive Procedural SQL implements SQL PSM and PL SQL MariaDB SQL PSM PL SQL SQL Persistent Stored Module implements SQL PSM Procedural Language SQL based on Ada 20 Microsoft Sybase T SQL Transact SQLMimer SQL SQL PSM SQL Persistent Stored Module implements SQL PSM MySQL SQL PSM SQL Persistent Stored Module implements SQL PSM MonetDB SQL PSM SQL Persistent Stored Module implements SQL PSM NuoDB SSP Starkey Stored ProceduresOracle PL SQL Procedural Language SQL based on Ada PostgreSQL PL pgSQL Procedural Language PostgreSQL Structured Query Language based on reduced PL SQL SAP R 3 ABAP Advanced Business Application ProgrammingSAP HANA SQLScript SQLScriptSybase Watcom SQL SQL Anywhere Watcom SQL DialectTeradata SPL Stored Procedural Language In addition to the standard SQL PSM extensions and proprietary SQL extensions procedural and object oriented programmability is available on many SQL platforms via DBMS integration with other languages The SQL standard defines SQL JRT extensions SQL Routines and Types for the Java Programming Language to support Java code in SQL databases Microsoft SQL Server 2005 uses the SQLCLR SQL Server Common Language Runtime to host managed NET assemblies in the database while prior versions of SQL Server were restricted to unmanaged extended stored procedures primarily written in C PostgreSQL lets users write functions in a wide variety of languages including Perl Python Tcl JavaScript PL V8 and C 21 Interoperability and standardization EditOverview Edit SQL implementations are incompatible between vendors and do not necessarily completely follow standards In particular date and time syntax string concatenation NULLs and comparison case sensitivity vary from vendor to vendor Particular exceptions are PostgreSQL 22 and Mimer SQL 23 which strive for standards compliance though PostgreSQL does not adhere to the standard in all cases For example the folding of unquoted names to lower case in PostgreSQL is incompatible with the SQL standard 24 which says that unquoted names should be folded to upper case 25 Thus Foo should be equivalent to FOO not foo according to the standard Popular implementations of SQL commonly omit support for basic features of Standard SQL such as the DATE or TIME data types The most obvious such examples and incidentally the most popular commercial and proprietary SQL DBMSs are Oracle whose DATE behaves as DATETIME 26 27 and lacks a TIME type 28 and MS SQL Server before the 2008 version As a result SQL code can rarely be ported between database systems without modifications Reasons for incompatibility Edit Several reasons for this lack of portability between database systems include The complexity and size of the SQL standard means that most implementers do not support the entire standard The standard does not specify database behavior in several important areas e g indices file storage leaving implementations to decide how to behave The SQL standard precisely specifies the syntax that a conforming database system must implement However the standard s specification of the semantics of language constructs is less well defined leading to ambiguity Many database vendors have large existing customer bases where the newer version of the SQL standard conflicts with the prior behavior of the vendor s database the vendor may be unwilling to break backward compatibility Little commercial incentive exists for vendors to make changing database suppliers easier see vendor lock in Users evaluating database software tend to place other factors such as performance higher in their priorities than standards conformance Standardization history Edit SQL was adopted as a standard by the ANSI in 1986 as SQL 86 29 and the ISO in 1987 11 It is maintained by ISO IEC JTC 1 Information technology Subcommittee SC 32 Data management and interchange Until 1996 the National Institute of Standards and Technology NIST data management standards program certified SQL DBMS compliance with the SQL standard Vendors now self certify the compliance of their products 30 The original standard declared that the official pronunciation for SQL was an initialism ˌ ɛ s ˌ k juː ˈ ɛ l ess cue el 9 Regardless many English speaking database professionals including Donald Chamberlin himself 31 use the acronym like pronunciation of ˈ s iː k w el sequel 32 mirroring the language s prerelease development name SEQUEL 13 14 31 The SQL standard has gone through a number of revisions Year Name Alias Comments1986 SQL 86 SQL 87 First formalized by ANSI1989 SQL 89 FIPS 127 1 Minor revision that added integrity constraints adopted as FIPS 127 11992 SQL 92 SQL2 FIPS 127 2 Major revision ISO 9075 Entry Level SQL 92 adopted as FIPS 127 21999 SQL 1999 SQL3 Added regular expression matching recursive queries e g transitive closure triggers support for procedural and control of flow statements nonscalar types arrays and some object oriented features e g structured types support for embedding SQL in Java SQL OLB and vice versa SQL JRT 2003 SQL 2003 Introduced XML related features SQL XML window functions standardized sequences and columns with autogenerated values including identity columns 2006 SQL 2006 ISO IEC 9075 14 2006 defines ways that SQL can be used with XML It defines ways of importing and storing XML data in an SQL database manipulating it within the database and publishing both XML and conventional SQL data in XML form In addition it lets applications integrate queries into their SQL code with XQuery the XML Query Language published by the World Wide Web Consortium W3C to concurrently access ordinary SQL data and XML documents 33 2008 SQL 2008 Legalizes ORDER BY outside cursor definitions Adds INSTEAD OF triggers TRUNCATE statement 34 FETCH clause2011 SQL 2011 Adds temporal data PERIOD FOR 35 more information at Temporal database History Enhancements for window functions and FETCH clause 36 2016 SQL 2016 Adds row pattern matching polymorphic table functions JSON2019 SQL 2019 Adds Part 15 multidimensional arrays MDarray type and operators Current standard Edit The standard is commonly denoted by the pattern ISO IEC 9075 n yyyy Part n title or as a shortcut ISO IEC 9075 ISO IEC 9075 is complemented by ISO IEC 13249 SQL Multimedia and Application Packages SQL MM which defines SQL based interfaces and packages to widely spread applications such as video audio and spatial data Interested parties may purchase SQL standards documents from ISO 37 IEC or ANSI A draft of SQL 2008 is freely available as a zip archive 38 Anatomy of SQL Standard Edit The SQL standard is divided into 10 parts but with gaps in the numbering due to the withdrawal of outdated parts ISO IEC 9075 1 2016 Part 1 Framework SQL Framework It provides logical concepts 39 ISO IEC 9075 2 2016 Part 2 Foundation SQL Foundation It contains the most central elements of the language and consists of both mandatory and optional features ISO IEC 9075 3 2016 Part 3 Call Level Interface SQL CLI It defines interfacing components structures procedures variable bindings that can be used to execute SQL statements from applications written in Ada C respectively C COBOL Fortran MUMPS Pascal or PL I For Java see part 10 SQL CLI is defined in such a way that SQL statements and SQL CLI procedure calls are treated as separate from the calling application s source code Open Database Connectivity is a well known superset of SQL CLI This part of the standard consists solely of mandatory features ISO IEC 9075 4 2016 Part 4 Persistent stored modules SQL PSM It standardizes procedural extensions for SQL including flow of control condition handling statement condition signals and resignals cursors and local variables and assignment of expressions to variables and parameters In addition SQL PSM formalizes declaration and maintenance of persistent database language routines e g stored procedures This part of the standard consists solely of optional features ISO IEC 9075 9 2016 Part 9 Management of External Data SQL MED It provides extensions to SQL that define foreign data wrappers and datalink types to allow SQL to manage external data External data is data that is accessible to but not managed by an SQL based DBMS This part of the standard consists solely of optional features ISO IEC 9075 10 2016 Part 10 Object language bindings SQL OLB It defines the syntax and semantics of SQLJ which is SQL embedded in Java see also part 3 The standard also describes mechanisms to ensure binary portability of SQLJ applications and specifies various Java packages and their contained classes This part of the standard consists solely of optional features Unlike SQL OLB JDBC defines an API and is not part of the SQL standard citation needed ISO IEC 9075 11 2016 Part 11 Information and definition schemas SQL Schemata It defines the Information Schema and Definition Schema providing a common set of tools to make SQL databases and objects self describing These tools include the SQL object identifier structure and integrity constraints security and authorization specifications features and packages of ISO IEC 9075 support of features provided by SQL based DBMS implementations SQL based DBMS implementation information and sizing items and the values supported by the DBMS implementations 40 This part of the standard contains both mandatory and optional features ISO IEC 9075 13 2016 Part 13 SQL Routines and types using the Java TM programming language SQL JRT It specifies the ability to invoke static Java methods as routines from within SQL applications Java in the database It also calls for the ability to use Java classes as SQL structured user defined types This part of the standard consists solely of optional features ISO IEC 9075 14 2016 Part 14 XML Related Specifications SQL XML It specifies SQL based extensions for using XML in conjunction with SQL The XML data type is introduced as well as several routines functions and XML to SQL data type mappings to support manipulation and storage of XML in an SQL database 33 This part of the standard consists solely of optional features citation needed ISO IEC 9075 15 2019 Part 15 Multi dimensional arrays SQL MDA It specifies a multidimensional array type MDarray for SQL along with operations on MDarrays MDarray slices MDarray cells and related features This part of the standard consists solely of optional features Extensions to the ISO IEC Standard Edit ISO IEC 9075 is complemented by ISO IEC 13249 SQL Multimedia and Application Packages This closely related but separate standard is developed by the same committee It defines interfaces and packages based on SQL The aim is a unified access to typical database applications like text pictures data mining or spatial data ISO IEC 13249 1 2016 Part 1 Framework ISO IEC 13249 2 2003 Part 2 Full Text ISO IEC 13249 3 2016 Part 3 Spatial ISO IEC 13249 5 2003 Part 5 Still image ISO IEC 13249 6 2006 Part 6 Data mining ISO IEC 13249 7 2013 Part 7 History ISO IEC 13249 8 xxxx Part 8 Metadata Registry Access MRA work in progress Technical reports Edit ISO IEC 9075 is also accompanied by a series of Technical Reports published as ISO IEC TR 19075 These Technical Reports explain the justification for and usage of some features of SQL giving examples where appropriate The Technical Reports are non normative if there is any discrepancy from 9075 the text in 9075 holds Currently available 19075 Technical Reports are ISO IEC TR 19075 1 2011 Part 1 XQuery Regular Expression Support in SQL ISO IEC TR 19075 2 2015 Part 2 SQL Support for Time Related Information ISO IEC TR 19075 3 2015 Part 3 SQL Embedded in Programs using the Java programming language ISO IEC TR 19075 4 2015 Part 4 SQL with Routines and types using the Java programming language ISO IEC TR 19075 5 2016 Part 5 Row Pattern Recognition in SQL ISO IEC TR 19075 6 2017 Part 6 SQL support for JavaScript Object Notation JSON ISO IEC TR 19075 7 2017 Part 7 Polymorphic table functions in SQL ISO IEC TR 19075 8 2019 Part 8 Multi Dimensional Arrays SQL MDA ISO IEC TR 19075 9 2020 Part 9 Online analytic processing OLAP capabilitiesAlternatives EditA distinction should be made between alternatives to SQL as a language and alternatives to the relational model itself Below are proposed relational alternatives to the SQL language See navigational database and NoSQL for alternatives to the relational model QL object oriented Datalog 4D Query Language 4D QL Datalog critics suggest that Datalog has two advantages over SQL it has cleaner semantics which facilitates program understanding and maintenance and it is more expressive in particular for recursive queries 41 HTSQL URL based query method IBM Business System 12 IBM BS12 one of the first fully relational database management systems introduced in 1982 ISBL jOOQ SQL implemented in Java as an internal domain specific language Java Persistence Query Language JPQL The query language used by the Java Persistence API and Hibernate persistence library JavaScript MongoDB implements its query language in a JavaScript API LINQ Runs SQL statements written like language constructs to query collections directly from inside Net code Object Query Language QBE Query By Example created by Moshe Zloof IBM 1977 QUEL introduced in 1974 by the U C Berkeley Ingres project closer to tuple relational calculus than SQL Tutorial D XQueryDistributed SQL processing EditDistributed Relational Database Architecture DRDA was designed by a work group within IBM from 1988 to 1994 DRDA enables network connected relational databases to cooperate to fulfill SQL requests 42 43 An interactive user or program can issue SQL statements to a local RDB and receive tables of data and status indicators in reply from remote RDBs SQL statements can also be compiled and stored in remote RDBs as packages and then invoked by package name This is important for the efficient operation of application programs that issue complex high frequency queries It is especially important when the tables to be accessed are located in remote systems The messages protocols and structural components of DRDA are defined by the Distributed Data Management Architecture Distributed SQL processing ala DRDA is distinctive from contemporary distributed SQL databases Criticisms EditDesign Edit SQL deviates in several ways from its theoretical foundation the relational model and its tuple calculus In that model a table is a set of tuples while in SQL tables and query results are lists of rows the same row may occur multiple times and the order of rows can be employed in queries e g in the LIMIT clause Critics argue that SQL should be replaced with a language that returns strictly to the original foundation for example see The Third Manifesto Orthogonality and completeness Edit Early specifications did not support major features such as primary keys Result sets could not be named and subqueries had not been defined These were added in 1992 12 The lack of sum types have been described as a roadblock to full use of SQL s user defined types JSON support for example needs to be added by a new standard in 2016 44 Null Edit The concept of Null is the subject of some debates The Null marker indicates the absence of a value and is distinct from a value of 0 for an integer column or an empty string for a text column The concept of Nulls enforces the 3 valued logic in SQL which is a concrete implementation of the general 3 valued logic 12 Duplicates Edit Another popular criticism is that it allows duplicate rows making integration with languages such as Python whose data types might make accurately representing the data difficult 12 in terms of parsing and by the absence of modularity 45 This is usually avoided by declaring a primary key or a unique constraint with one or more columns that uniquely identifies a row in the table Impedance mismatch Edit In a similar sense to object relational impedance mismatch a mismatch occurs between the declarative SQL language and the procedural languages in which SQL is typically embedded SQL data types EditThe SQL standard defines three kinds of data types citation needed predefined data types constructed types user defined types Constructed types are one of ARRAY MULTISET REF erence or ROW User defined types are comparable to classes in object oriented language with their own constructors observers mutators methods inheritance overloading overwriting interfaces and so on Predefined data types are intrinsically supported by the implementation Predefined data types Edit Character typesCharacter CHAR Character varying VARCHAR Character large object CLOB National character typesNational character NCHAR National character varying NCHAR VARYING National character large object NCLOB Binary typesBinary BINARY Binary varying VARBINARY Binary large object BLOB Numeric typesExact numeric types NUMERIC DECIMAL SMALLINT INTEGER BIGINT Approximate numeric types FLOAT REAL DOUBLE PRECISION Decimal floating point type DECFLOAT Datetime types DATE TIME TIMESTAMP Interval type INTERVAL Boolean XML JSONSee also EditWikibook SQL Object database List of relational database management systems Comparison of relational database management systems Comparison of object relational database management systems D data language specification Query by Example SQL syntax Oracle PL SQL Microsoft Transact SQL T SQL Online transaction processing OLTP Online analytical processing OLAP Data warehouse Relational data stream management system NoSQL MUMPS Hierarchical database model Star schema Snowflake schemaNotes Edit Formally SQL data statements excluding SQL data change statements this is primarily the Select statement Formally SQL schema statements Formally SQL data change statementsReferences Edit Paul Ryan A guided tour of the Microsoft Command Shell Ars Technica Retrieved 10 April 2011 Media Type registration for application sql Internet Assigned Numbers Authority 10 April 2013 Retrieved 10 April 2013 The application sql Media Type RFC 6922 Internet Engineering Task Force April 2013 p 3 Retrieved 10 April 2013 Beaulieu Alan April 2009 Mary E Treseler ed Learning SQL 2nd ed Sebastopol CA USA O Reilly ISBN 978 0 596 52083 0 Chamberlin Donald D 2001 10 03 Oral history interview with Donald D Chamberlin Retrieved 2020 01 14 We changed the original name SEQUEL to SQL because we got a letter from somebody s lawyer that said the name SEQUEL belonged to them We shortened it to SQL for Structured Query Language and the product was known as SQL DS SQL 92 4 22 SQL statements 4 22 1 Classes of SQL statements There are at least five ways of classifying SQL statements 4 22 2 SQL statements classified by function The following are the main classes of SQL statements SQL 2003 4 11 SQL statements and later revisions Chatham Mark 2012 Structured Query Language By Example Volume I Data Query Language p 8 ISBN 978 1 29119951 2 Codd Edgar F June 1970 A Relational Model of Data for Large Shared Data Banks Communications of the ACM 13 6 377 87 CiteSeerX 10 1 1 88 646 doi 10 1145 362384 362685 S2CID 207549016 a b Chapple Mike SQL Fundamentals Databases About com Retrieved 2009 01 28 Structured Query Language SQL International Business Machines October 27 2006 Retrieved 2007 06 10 a b ISO 9075 1987 Information technology Database languages SQL Part 1 Framework SQL Framework 1987 06 01 a b c d e f Chamberlin Donald 2012 Early History of SQL IEEE Annals of the History of Computing 34 4 78 82 doi 10 1109 MAHC 2012 61 S2CID 1322572 a b c Chamberlin Donald D Boyce Raymond F 1974 SEQUEL A Structured English Query Language PDF Proceedings of the 1974 ACM SIGFIDET Workshop on Data Description Access and Control Association for Computing Machinery 249 64 Archived from the original PDF on 2007 09 26 Retrieved 2007 06 09 a b Oppel Andy February 27 2004 Databases Demystified San Francisco CA McGraw Hill Osborne Media pp 90 1 ISBN 978 0 07 146960 9 History of IBM 1978 IBM Archives IBM Retrieved 2007 06 09 ISO ISO IEC JTC 1 SC 32 Data management and interchange www iso org Retrieved 2 January 2021 ANSI ISO IEC International Standard IS Database Language SQL Part 2 Foundation SQL Foundation 1999 IBM PureData System for Analytics Version 7 0 3 Invantive Procedural SQL CREATE PROCEDURE MariaDB KnowledgeBase Retrieved 2019 04 23 PostgreSQL contributors 2011 PostgreSQL server programming PostgreSQL 9 1 official documentation postgresql org Retrieved 2012 03 09 PostgreSQL contributors 2012 About PostgreSQL PostgreSQL 9 1 official website PostgreSQL Global Development Group Retrieved March 9 2012 PostgreSQL prides itself in standards compliance Its SQL implementation strongly conforms to the ANSI SQL 2008 standard Mimer SQL Built on Standards Mimer SQL official website Mimer Information Technology 2009 4 1 Lexical Structure PostgreSQL documentation 2018 Second Informal Review Draft ISO IEC 9075 1992 Database Language SQL Section 5 2 syntax rule 11 30 July 1992 Lorentz Diana Roeser Mary Beth Abraham Sundeep Amor Angela Arora Geeta Arora Vikas Ashdown Lance Baer Hermann Bellamkonda Shrikanth October 2010 1996 Basic Elements of Oracle SQL Data Types Oracle Database SQL Language Reference 11g Release 2 11 2 Oracle Database Documentation Library Redwood City CA Oracle USA Inc Retrieved December 29 2010 For each DATE value Oracle stores the following information century year month date hour minute and second Lorentz Diana Roeser Mary Beth Abraham Sundeep Amor Angela Arora Geeta Arora Vikas Ashdown Lance Baer Hermann Bellamkonda Shrikanth October 2010 1996 Basic Elements of Oracle SQL Data Types Oracle Database SQL Language Reference 11g Release 2 11 2 Oracle Database Documentation Library Redwood City CA Oracle USA Inc Retrieved December 29 2010 The datetime data types are DATE Lorentz Diana Roeser Mary Beth Abraham Sundeep Amor Angela Arora Geeta Arora Vikas Ashdown Lance Baer Hermann Bellamkonda Shrikanth October 2010 1996 Basic Elements of Oracle SQL Data Types Oracle Database SQL Language Reference 11g Release 2 11 2 Oracle Database Documentation Library Redwood City CA Oracle USA Inc Retrieved December 29 2010 Do not define columns with the following SQL DS and DB2 data types because they have no corresponding Oracle data type TIME Finding Aid X3H2 Records 1978 95 American National Standards Institute Doll Shelley June 19 2002 Is SQL a Standard Anymore TechRepublic s Builder com TechRepublic Archived from the original on 2012 07 05 Retrieved 2016 04 12 a b Gillespie Patrick Pronouncing SQL S Q L or Sequel Retrieved 12 February 2012 Melton Jim Alan R Simon 1993 1 2 What is SQL Understanding the New SQL A Complete Guide Morgan Kaufmann p 536 ISBN 978 1 55860 245 8 SQL correctly pronounced ess cue ell instead of the somewhat common sequel a b Wagner Michael 2010 SQL XML 2006 Evaluierung der Standardkonformitat ausgewahlter Datenbanksysteme Diplomica Verlag p 100 ISBN 978 3 8366 9609 8 SQL 2008 now an approved ISO international standard Sybase July 2008 Archived from the original on 2011 06 28 Krishna Kulkarni Jan Eike Michels September 2012 Temporal features in SQL 2011 PDF SIGMOD Record 41 3 Fred Zemke 2012 What s new in SQL 2011 PDF Oracle Corporation ISO IEC 9075 2 2016 Information technology Database languages SQL Part 2 Foundation SQL Foundation December 2016 SQL 2008 draft Zip Whitemarsh Information Systems Corporation ISO IEC 9075 1 2016 Information technology Database languages SQL Part 1 Framework SQL Framework ISO IEC 9075 11 2008 Information and Definition Schemas SQL Schemata Fernando Saenz Perez Outer Joins in a Deductive Database System PDF Lbd udc es Retrieved 2017 01 16 Reinsch R 1988 Distributed database for SAA IBM Systems Journal 27 3 362 389 doi 10 1147 sj 273 0362 Distributed Relational Database Architecture Reference IBM Corp SC26 4651 0 1990 Brandon Jamie July 2021 Against SQL Retrieved 2 August 2021 Schauder Jen Why SQL Sucks Schauderhaft Retrieved 3 February 2018 Sources EditCodd Edgar F June 1970 A Relational Model of Data for Large Shared Data Banks Communications of the ACM 13 6 377 87 doi 10 1145 362384 362685 S2CID 207549016 Archived from the original on 2007 06 12 Discussion on alleged SQL flaws C2 wiki C J Date with Hugh Darwen A Guide to the SQL standard a users guide to the standard database language SQL 4th ed Addison Wesley USA 1997 ISBN 978 0 201 96426 4 SQL standards documents Edit ITTF publicly available standards and technical reports Edit The ISO IEC Information Technology Task Force publishes publicly available standards including SQL Technical Corrigenda corrections and Technical Reports discussion documents are published there SQL Part 1 Framework SQL Framework Draft documents Edit Formal SQL standards are available from ISO and ANSI for a fee For informative use as opposed to strict standards compliance late drafts often suffice SQL 2011 draft SQL 92 draftExternal links EditSQLat Wikipedia s sister projects Definitions from Wiktionary Media from Wikimedia Commons Textbooks from Wikibooks Resources from Wikiversity 1995 SQL Reunion People Projects and Politics by Paul McJones ed transcript of a reunion meeting devoted to the personal history of relational databases and SQL American National Standards Institute X3H2 Records 1978 1995 Charles Babbage Institute Collection documents the H2 committee s development of the NDL and SQL standards Oral history interview with Donald D Chamberlin Charles Babbage Institute In this oral history Chamberlin recounts his early life his education at Harvey Mudd College and Stanford University and his work on relational database technology Chamberlin was a member of the System R research team and with Raymond F Boyce developed the SQL database language Chamberlin also briefly discusses his more recent research on XML query languages Comparison of Different SQL Implementations This comparison of various SQL implementations is intended to serve as a guide to those interested in porting SQL code between various RDBMS products and includes comparisons between SQL 2008 PostgreSQL DB2 MS SQL Server MySQL Oracle and Informix Event stream processing with SQL An introduction to real time processing of streaming data with continuous SQL queries BNF Grammar for ISO IEC 9075 2003 part 2 SQL Framework Retrieved from https en wikipedia org w index php title SQL amp oldid 1047667985, wikipedia, wiki, book,

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