2.1.1. SQL Flavours

Distinct subsets of SQL apply to different sectors of activity. The SQL subsets in Firebird’s language implementation are:

• Dynamic SQL (DSQL)

• Procedural SQL (PSQL)

• Embedded SQL (ESQL)

• Interactive SQL (ISQL)

Dynamic SQL is the major part of the language which corresponds to the Part 2 (SQL/Foundation) part of the SQL specification. DSQL represents statements passed by client applications through the public Firebird API and processed by the database engine.

Procedural SQL augments Dynamic SQL to allow compound statements containing local variables, assignments, conditions, loops and other procedural constructs. PSQL corresponds to the Part 4 (SQL/PSM) part of the SQL specifications. Originally, PSQL extensions were available in persistent stored modules (procedures and triggers) only, but in more recent releases they were surfaced in Dynamic SQL as well (see ).

Embedded SQL defines the DSQL subset supported by Firebird gpre, the application which allows you to embed SQL constructs into your host programming language (C, C++, Pascal, Cobol, etc.) and preprocess those embedded constructs into the proper Firebird API calls.

Both DSQL and PSQL subsets are completely presented in this reference. Neither ESQL nor ISQL flavours are described here unless mentioned explicitly.

2.1.2. SQL Dialects

SQL dialect is a term that defines the specific features of the SQL language that are available when accessing a database. SQL dialects can be defined at the database level and specified at the connection level. Three dialects are available:

2.1.3. Error Conditions

Processing of every SQL statement either completes successfully or fails due to a specific error condition.