Code SQL statements in PL/I applications

This topic describes the unique application and coding requirements for embedding SQL statements in an iSeries™ PL/I program. Requirements for host structures and host variables are defined.

• Define the SQL communications area in PL/I applications that use SQL
  A PL/I program that contains SQL statements must include one or both of the following:
• Define SQL descriptor areas in PL/I applications that use SQL
  There are two types of SQL descriptor areas. One is defined with the ALLOCATE DESCRIPTOR statement. The other is defined using the SQLDA structure. In this section, only the SQLDA form is discussed.
• Embed SQL statements in PL/I applications that use SQL
  The first statement of the PL/I program must be a PROCEDURE statement.
• Use host variables in PL/I applications that use SQL
  All host variables used in SQL statements must be explicitly declared.
• Use host structures in PL/I applications that use SQL
  In PL/I programs, you can define a host structure, which is a named set of elementary PL/I variables. A host structure name can be a group name whose subordinate levels name elementary PL/I variables.
• Use host structure arrays in PL/I applications that use SQL
  In PL/I programs, you can define a host structure array.
• Use external file descriptions in PL/I applications that use SQL
  You can use the PL/I %INCLUDE directive to include the definitions of externally described files in a source program.
• Determine equivalent SQL and PL/I data types
  The precompiler determines the base SQLTYPE and SQLLEN of host variables based on the following table.
• Use indicator variables in PL/I applications that use SQL
  An indicator variable is a two-byte integer (BIN FIXED(p), where p is 1 to 15).
• Differences in PL/I because of structure parameter passing techniques
  The PL/I precompiler attempts to use the structure parameter passing technique, if possible. This structure parameter passing technique provides better performance for most PL/I programs using SQL.