SQL Wikipedia. SQL listenESS kew EL4 or listenSEE kwl,5Structured Query Language6789 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.In comparison to older readwrite APIs like ISAM or VSAM, SQL offers two main advantages First, it introduced the concept of accessing many records with one single command, and second, it eliminates the need to specify how to reach a record, e.Originally based upon relational algebra and tuple relational calculus, SQL consists of a data definition language, data manipulation language, and data control language.The scope of SQL includes data insert, query, update and delete, schema creation and modification, and data access control.Although SQL is often described as, and to a great extent is, a declarative language 4.GL, it also includes procedural elements.SQL was one of the first commercial languages for Edgar F.Codds relational model, as described in his influential 1.A Relational Model of Data for Large Shared Data Banks.Access Form To Update Sql Table Statement' title='Access Form To Update Sql Table Statement' />Thus far in this tips series on Access and SQL Server, we have created an ODBC Data Source Name DSN using the OLEDB driver for connecting to SQL Server 2000, as.The SQL language is subdivided into several language elements, including Clauses, which are constituent components of statements and queries.In some cases, these.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 1.International Organization for Standardization ISO in 1.Since then, the standard has been revised to include a larger set of features.Despite the existence of such standards, most SQL code is not completely portable among different database systems without adjustments.HistoryeditSQL was initially developed at IBM by Donald D.Chamberlin and Raymond F.Boyce in the early 1.Access and SQL Part 2 Putting VBA and SQL Together.In the first tutorial in this series on Access and SQL I explained where SQL fitted into the overall Access picture.MSAccessGUID1.jpg' alt='Access Form To Update Sql Table Statement' title='Access Form To Update Sql Table Statement' />This version, initially called SEQUEL Structured English Query Language, was designed to manipulate and retrieve data stored in IBMs original quasi relational database management system, System R, which a group at IBM San Jose Research Laboratory had developed during the 1.The acronym SEQUEL was later changed to SQL because SEQUEL was a trademark of the UK based.Hawker Siddeley aircraft company.In the late 1. 97.Relational Software, Inc.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 1. 97. 9, Relational Software, Inc.SQL, Oracle V2 Version.VAX computers. 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 System3.SQLDS, and DB2, which were commercially available in 1.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.LIMIT clause. Critics argue that SQL should be replaced with a language that strictly returns to the original foundation for example, see The Third Manifesto.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 3.VL truefalseunknown or Booleantruth values and are used to limit the effects of statements and queries, or to change program flow. Ms Dos Hacking Game Server . 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 extensionseditSQL 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 In addition to the standard SQLPSM 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 SQLJRT extensions SQL Routines and Types for the Java Programming Language to support Java code in SQL databases.SQL Server 2. 00.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.Postgre. SQL lets users write functions in a wide variety of languagesincluding Perl, Python, Tcl, Java.Script PLV8 and C.Interoperability and standardizationeditSQL 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 Postgre.SQL2. 0 and Mimer SQL2.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,2.TIME type2. 4 and MS SQL Server before the 2.As a result, SQL code can rarely be ported between database systems without modifications.There are several reasons for this lack of portability between database systems The complexity and size of the SQL standard means that most implementors do not support the entire standard.The standard does not specify database behavior in several important areas e.The SQL standard precisely specifies the syntax that a conforming database system must implement.However, the standards 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 vendors database, the vendor may be unwilling to break backward compatibility.There is little commercial incentive for vendors to make it easier for users to change database suppliers see vendor lock in.Users evaluating database software tend to place other factors such as performance higher in their priorities than standards conformance.SQL was adopted as a standard by the American National Standards Institute ANSI in 1.SQL 8. 62. 5 and the International Organization for Standardization ISO in 1.It is maintained by ISOIEC JTC 1, Information technology, Subcommittee SC 3.Data management and interchange.The standard is commonly denoted by the pattern ISOIEC 9.Part n title, or, as a shortcut, ISOIEC 9.ISOIEC 9. 07. 5 is complemented by ISOIEC 1.SQL Multimedia and Application Packages SQLMM, which defines SQL based interfaces and packages to widely spread applications like video, audio and spatial data.Until 1. 99. 6, 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 es queue el.Regardless, many English speaking database professionals including Donald Chamberlin himself5 use the acronym like pronunciation of sequel,2.SEQUEL. 1. 41. The SQL standard has gone through a number of revisions Year.Name. Alias. Comments.SQL 8. 6SQL 8. 7First formalized by ANSI.SQL 8. 9FIPS 1. 27 1.Minor revision that added integrity constraints, adopted as FIPS 1.SQL 9. 2SQL2, FIPS 1.
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