Code SQL statements in ILE RPG applications

This topic describes the unique application and coding requirements for embedding SQL statements in an ILE RPG program. The coding requirements for host variables are defined.

For more information about programming using ILE RPG, see the ILE RPG Programmer's Guide topic and the ILE RPG Reference topic.

• Define the SQL communications area in ILE RPG applications that use SQL
  The SQL precompiler automatically places the SQLCA in the definition specifications of the ILE RPG program prior to the first calculation specification, unless a SET OPTION SQLCA = *NO statement is found.
• Define SQL descriptor areas in ILE RPG 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 ILE RPG applications that use SQL
  SQL statements coded in an ILE RPG program must be placed in the calculation section.
• Use host variables in ILE RPG applications that use SQL
  All host variables used in SQL statements must be explicitly declared.
• Use host structures in ILE RPG applications that use SQL
  The ILE RPG data structure name can be used as a host structure name if subfields exist in the data structure. The use of the data structure name in an SQL statement implies the list of subfield names making up the data structure.
• Use host structure arrays in ILE RPG applications that use SQL
  A host structure array is defined as an occurrence data structure or a data structure with the keyword DIM coded. Both types of data structures can be used on the SQL FETCH or INSERT statement when processing multiple rows.
• Use external file descriptions in ILE RPG applications that use SQL
  Field definitions for externally described files, including renaming of fields, are recognized by the SQL precompiler. The external definition form of the data structure can be used to obtain a copy of the column names to be used as host variables.
• Determine equivalent SQL and ILE RPG data types
  The precompiler determines the base SQLTYPE and SQLLEN of host variables according to the following table. If a host variable appears with an indicator variable, the SQLTYPE is the base SQLTYPE plus one.
• Use indicator variables in ILE RPG applications that use SQL
  An indicator variable is a binary field with length less than 5 (2 bytes).
• Example of the SQLDA for a multiple row-area fetch in ILE RPG applications that use SQL
  The following is an example of the SQLDA for a multiple row-area fetch in ILE RPG.
• Example of dynamic SQL in an ILE RPG application that uses SQL
  The following is an example of using dynamic SQL in ILE RPG.