SQL Dialects

Many database vendors provide their own dialect of SQL to supplement the standard.  For example, conditional processing, error handling, and flow-of-control statements are often provided by database vendors as an element of their own dialect of the SQL standard.

The ANSI SQL standard SQL/PSM (Persistent Stored Module) package describes many features associated with programming stored procedures and incorporates many of the extensions offered by these dialects.  However, the implementation of SQL/PSM is not consistent or reliable across all database vendors.

Some popular dialects of SQL include:

Found in Oracle. PL/SQL stands for Procedural Language/SQL and contains many similarities to the language Ada.

Used by both Microsoft SQL Server and Sybase Adaptive Server. As Microsoft and Sybase have moved away from the common platform they shared early in the 1990s, their implementations of Transact-SQL have also diverged.

The SQL dialect and extensions implemented in PostgreSQL. The acronym stands for Procedural Language/postgreSQL.

The procedural language extensions found in IBM’s DB2 UDB database platform.
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SQL History and Implementation

SQL has a long history starting way back in the mid-1980′s.

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Introduction to the Relational Model and ANSI SQL

A quick introduction to the most basic concepts in relational databases and in ANSI SQL.

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ALL Operator

The ALL operator checks a list of values to ensure that all values meet the criteria.

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BETWEEN operator

BETWEEN performs a Boolean True/False test to decide whether or not a value falls within a particular range.

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Codd’s Rules for Relational Database Systems

The fundamentals of relation database behavior were first devised by E. F. Codd.

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ANY / SOME operators

The ANY | SOME operators are synonyms of IN and EXISTS, checking values to determine if one or more match the criteria.

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SQL Statement Classes

A description of the most commonly referenced subsets of the ANSI SQL standard.

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What Is a Relational Database?

These days, relational database management systems (RDBMSs) like Microsoft SQL Server and Oracle are the primary engines of information systems everywhere, particularly for enterprise computing systems and web applications. Though RDBMSs are now common enough to trip over, it wasn’t always that way.

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