Rational Developer for System z
Enterprise PL/I for z/OS, Version 3.8, Programming Guide

Coding SQL statements in PL/I applications

You can code SQL statements in your PL/I applications using the language defined in DB2 UDB for z/OS SQL Reference. Specific requirements for your SQL code are described in the sections that follow.

Defining the SQL communications area

A PL/I program that contains SQL statements must include either an SQLCODE variable (if the STDSQL(86) preprocessor option is used) or an SQL communications area (SQLCA). As shown in Figure 5, part of an SQLCA consists of an SQLCODE variable and an SQLSTATE variable.

The SQLCA declaration should be included by using the EXEC SQL INCLUDE statement:

  exec sql include sqlca;

The SQLCA structure must not be defined within an SQL declare section. The scope of the SQLCODE and SQLSTATE declarations must include the scope of all SQL statements in the program.

Figure 5. The PL/I declaration of SQLCA
  Dcl
    1 Sqlca,
      2 sqlcaid      char(8),           /* Eyecatcher = 'SQLCA   '   */
      2 sqlcabc      fixed binary(31),  /* SQLCA size in bytes = 136 */
      2 sqlcode      fixed binary(31),  /* SQL return code           */
      2 sqlerrmc     char(70) var,      /* Error message tokens      */
      2 sqlerrp      char(8),           /* Diagnostic information    */
      2 sqlerrd(0:5) fixed binary(31),  /* Diagnostic information    */
      2 sqlwarn,                        /* Warning flags             */
        3 sqlwarn0   char(1),
        3 sqlwarn1   char(1),
        3 sqlwarn2   char(1),
        3 sqlwarn3   char(1),
        3 sqlwarn4   char(1),
        3 sqlwarn5   char(1),
        3 sqlwarn6   char(1),
        3 sqlwarn7   char(1),
      2 sqlext,
        3 sqlwarn8   char(1),
        3 sqlwarn9   char(1),
        3 sqlwarna   char(1),
        3 sqlstate   char(5);       /* State corresponding to SQLCODE */

Defining SQL descriptor areas

The following statements require an SQLDA:

Unlike the SQLCA, there can be more than one SQLDA in a program, and an SQLDA can have any valid name. An SQLDA should be included by using the EXEC SQL INCLUDE statement:

  exec sql include sqlda;

The SQLDA must not be defined within an SQL declare section.

Figure 6. The PL/I declaration of an SQL descriptor area
  Dcl
    1 Sqlda based(Sqldaptr),
      2 sqldaid     char(8),          /* Eye catcher = 'SQLDA   ' */
      2 sqldabc     fixed binary(31), /* SQLDA size in bytes=16+44*SQLN*/
      2 sqln        fixed binary(15), /* Number of SQLVAR elements*/
      2 sqld        fixed binary(15), /* # of used SQLVAR elements*/
      2 sqlvar(Sqlsize refer(sqln)),  /* Variable Description     */
        3 sqltype   fixed binary(15), /* Variable data type       */
        3 sqllen    fixed binary(15), /* Variable data length     */
        3 sqldata   pointer,          /* Pointer to variable data value*/
        3 sqlind    pointer,          /* Pointer to Null indicator*/
        3 sqlname   char(30) var ;    /* Variable Name            */

  Dcl
    1 Sqlda2 based(Sqldaptr),
      2 sqldaid2     char(8),          /* Eye catcher = 'SQLDA   ' */
      2 sqldabc2     fixed binary(31), /* SQLDA size in bytes=16+44*SQLN*/
      2 sqln2        fixed binary(15), /* Number of SQLVAR elements*/
      2 sqld2        fixed binary(15), /* # of used SQLVAR elements*/
      2 sqlvar2(Sqlsize refer(sqln2)), /* Variable Description     */
        3 sqlbiglen,
          4 sqllongl fixed binary(31),
          4 sqlrsvdl fixed binary(31),
        3 sqldatal   pointer,
        3 sqltname   char(30) var;

  dcl Sqlsize    fixed binary(15);     /* number of sqlvars (sqln) */
  dcl Sqldaptr   pointer;
  dcl Sqltripled char(1) initial('3');
  dcl Sqldoubled char(1) initial('2');
  dcl Sqlsingled char(1) initial(' ');

Embedding SQL statements

The first statement of your program must be a PROCEDURE or a PACKAGE statement. You can add SQL statements to your program wherever executable statements can appear. Each SQL statement must begin with EXEC (or EXECUTE) SQL and end with a semicolon (;).

For example, an UPDATE statement might be coded as follows:

  exec sql update DSN8710.DEPT
           set   Mgrno  = :Mgr_Num
           where Deptno = :Int_Dept;
Comments

In addition to SQL statements, comments can be included in embedded SQL statements wherever a blank is allowed.

SQL style comments ('--') are supported when embedded in SQL statements beginning with Enterprise PL/I V3R6.

Continuation for SQL statements

The line continuation rules for SQL statements are the same as those for other PL/I statements.

Including code

SQL statements or PL/I host variable declaration statements can be included by placing the following SQL statement at the point in the source code where the statements are to be embedded:

  exec sql include member;
Margins

SQL statements must be coded in columns m through n where m and n are specified in the MARGINS(m,n) compiler option.

Names

Any valid PL/I variable name can be used for a host variable. The length of a host variable name must not exceed the value n specified in the LIMITS(NAME(n)) compiler option.

Statement labels

With the exception of the END DECLARE SECTION statement, and the INCLUDE text-file-name statement, executable SQL statements, like PL/I statements, can have a label prefix.

WHENEVER statement

The target for the GOTO clause in an SQL WHENEVER statement must be a label in the PL/I source code and must be within the scope of any SQL statements affected by the WHENEVER statement.

Using host variables

All host variables used in SQL statements must be explicitly declared. If the ONEPASS option is in effect, a host variable used in an SQL statement must be declared prior to its first use in an SQL statement.

In addition:

Declaring host variables

Host variable declarations can be made at the same place as regular PL/I variable declarations.

Only a subset of valid PL/I declarations are recognized as valid host variable declarations. The preprocessor does not use the data attribute defaults specified in the PL/I DEFAULT statement. If the declaration for a variable is not recognized, any statement that references the variable might result in the message :

'The host variable token ID is not valid'

Only the names and data attributes of the variables are used by the preprocessor; the alignment, scope, and storage attributes are ignored.

Numeric host variables

The following figure shows the syntax for valid numeric host variable declarations.

Read syntax diagramSkip visual syntax diagram>>-+-DECLARE-+--+-variable-name---------+----------------------->
   '-DCL-----'  |   .-,-------------.   |
                |   V               |   |
                '-(---variable-name-+-)-'
 
>----+---------+-+-FIXED--+-------------------------+-+--------->
     +-BINARY--+ |        '-(precision-+--------+-)-' |
     +-BIN-----+ |                     '-,scale-'     |
     +-DECIMAL-+ '-FLOAT-+-----------------+----------'
     '-DEC-----'         '-(--precision--)-'
 
>--+---------------------------------------+-- ; --------------><
   '-Alignment and/or Scope and/or Storage-'
 

Notes

Character host variables

The following figure shows the syntax for valid character host variables.

Read syntax diagramSkip visual syntax diagram>>-+-DECLARE-+--+-variable-name---------+----------------------->
   '-DCL-----'  |   .-,-------------.   |
                |   V               |   |
                '-(---variable-name-+-)-'
 
>--+-CHARACTER-+--+----------+--+---------+--------------------->
   '-CHAR------'  '-(length)-'  +-VARYING-+
                                '-VAR-----'
 
>--+---------------------------------------+-- ; --------------><
   '-Alignment and/or Scope and/or Storage-'
 

Notes

Graphic host variables

The following figure shows the syntax for valid graphic host variables.

Read syntax diagramSkip visual syntax diagram>>-+-DECLARE-+--+-variable-name---------+----------------------->
   '-DCL-----'  |   .-,-------------.   |
                |   V               |   |
                '-(---variable-name-+-)-'
 
>--GRAPHIC--+----------+--+---------+--------------------------->
            '-(length)-'  +-VARYING-+
                          '-VAR-----'
 
>--+---------------------------------------+-- ; --------------><
   '-Alignment and/or Scope and/or Storage-'
 

Notes

Result set locators

The following figure shows the syntax for valid result set locator declarations.

Read syntax diagramSkip visual syntax diagram>>-+-DECLARE-+--+-variable-name---------+----------------------->
   '-DCL-----'  |   .-,-------------.   |
                |   V               |   |
                '-(---variable-name-+-)-'
 
>----SQL TYPE IS RESULT_SET_LOCATOR----+---------+-------------->
                                       +-VARYING-+
                                       '-VAR-----'
 
>--+---------------------------------------+-- ; --------------><
   '-Alignment and/or Scope and/or Storage-'
 
Table locators

The following figure shows the syntax for valid table locators.

Read syntax diagramSkip visual syntax diagram>>-+-DECLARE-+--+-variable-name---------+----------------------->
   '-DCL-----'  |   .-,-------------.   |
                |   V               |   |
                '-(---variable-name-+-)-'
 
>----SQL TYPE IS TABLE LIKE table-name AS LOCATOR---- ; -------><
 
LOB Variables and Locators

The following figure shows the syntax for declarations of BLOB, CLOB, and DBCLOB host variables and locators.

Read syntax diagramSkip visual syntax diagram>>-+-Declare-+--PL/I host identifier--SQL TYPE IS--------------->
   '-Dcl-----'
 
>--| PL/I LOB type |--| PL/I LOB type: |------------------------>
 
>--+-+-+-Binary Large Object-+----+--(--length--+---+--)-+-----><
   | | '-BLOB----------------'    |             +-K-+    |
   | +-+-Character Large Object-+-+             +-M-+    |
   | | +-Char Large Object------+ |             '-G-'    |
   | | '-CLOB-------------------' |                      |
   | '-DBCLOB---------------------'                      |
   '-+-BLOB_LOCATOR---+----------------------------------'
     +-CLOB_LOCATOR---+
     +-DBCLOB_LOCATOR-+
     +-BLOB_FILE------+
     +-CLOB_FILE------+
     '-DBCLOB_FILE----'
 
XML File References and LOB Variables

The following figure shows the syntax for declarations of the new "XML AS" file reference and LOB variable types.

Read syntax diagramSkip visual syntax diagram>>-+-Declare-+--PL/I host identifier--SQL TYPE IS XML AS-------->
   '-Dcl-----'
 
>--| PL/I LOB type |--| PL/I LOB type: |------------------------>
 
>--+-+-+-Binary Large Object-+----+--(--length--+---+--)-+-----><
   | | '-BLOB----------------'    |             +-K-+    |
   | +-+-Character Large Object-+-+             +-M-+    |
   | | +-Char Large Object------+ |             '-G-'    |
   | | '-CLOB-------------------' |                      |
   | '-DBCLOB---------------------'                      |
   '-+-BLOB_FILE---+-------------------------------------'
     +-CLOB_FILE---+
     '-DBCLOB_FILE-'
 

The following constant declarations are generated by the SQL preprocessor and can be used to set the file option variable when you use the file reference host variables:

DCL SQL_FILE_READ      FIXED BIN(31) VALUE(2);
DCL SQL_FILE_CREATE    FIXED BIN(31) VALUE(8);
DCL SQL_FILE_OVERWRITE FIXED BIN(31) VALUE(16);
DCL SQL_FILE_APPEND    FIXED BIN(31) VALUE(32);
ROWIDs

The following figure shows the syntax for valid declarations of ROWID variables.

Read syntax diagramSkip visual syntax diagram>>-+-DECLARE-+--+-variable-name---------+----------------------->
   '-DCL-----'  |   .-,-------------.   |
                |   V               |   |
                '-(---variable-name-+-)-'
 
>----SQL TYPE IS ROWID---- ; ----------------------------------><
 

Determining equivalent SQL and PL/I data types

The base SQLTYPE and SQLLEN of host variables are determined according to the following table. If a host variable appears with an indicator variable, the SQLTYPE is the base SQLTYPE plus one.

Table 7. SQL data types generated from PL/I declarations
    PL/I Data Type SQLTYPE of Host Variable SQLLEN of Host Variable SQL Data Type
BIN FIXED(n), n < 16 500 2 SMALLINT
BIN FIXED(n), n ranges from 16 to 31 496 4 INTEGER
BIN FIXED(n), n ranges from 32 to 63 492 8 BIGINT
DEC FIXED(p,s) 0<=p<=15 and 0<=s<=p 484   p (byte 1) s (byte 2) DECIMAL(p,s)
BIN FLOAT(p), 1 ≤ p ≤ 21 480 4 REAL or FLOAT(n) 1<=n<=21
BIN FLOAT(p), 22 ≤ p ≤ 53 480 8 DOUBLE PRECISION or FLOAT(n) 22<=n<=53
DEC FLOAT(m), 1 ≤ m ≤ 6 480 4 FLOAT (single precision)
DEC FLOAT(m), 7 ≤ m ≤ 16 480 8 FLOAT (double precision)
CHAR(n), 452 n CHAR(n)
CHAR(n) VARYING, 1 ≤ n ≤ 255 448 n VARCHAR(n)
CHAR(n) VARYING, n > 255 456 n VARCHAR(n)
GRAPHIC(n), 1 ≤ n ≤ 127 468 n GRAPHIC(n)
GRAPHIC(n) VARYING, 1 ≤ n ≤ 2000 464 n VARGRAPHIC(n)
GRAPHIC(n) VARYING, n > 2000 472 n LONG VARGRAPHIC
Table 8. SQL data types generated from Meta PL/I declarations
    PL/I Data Type SQLTYPE of Host Variable SQLLEN of Host Variable SQL Data Type
SQL TYPE IS BLOB(n) 1<n<2147483647 404 n BLOB(n)
SQL TYPE IS CLOB(n) 1<n<2147483647 408 n CLOB(n)
SQL TYPE IS DBCLOB(n) 1<n<1073741823 (2) 412 n DBCLOB(n) (2)
SQL TYPE IS ROWID 904 40 ROWID
SQL TYPE IS VARBINARY(n) 1<n<32704 908 n VARBINARY(n)
SQL TYPE IS BINARY(n) 1<n<255 912 n BINARY(n)
SQL TYPE IS BLOB_FILE 916 267 BLOB File Reference (1)
SQL TYPE IS CLOB_FILE 920 267 CLOB File Reference (1)
SQL TYPE IS DBCLOB_FILE 924 267 DBCLOB File Reference (1)
SQL TYPE IS BLOB_LOCATOR 960 4 BLOB Locator (1)
SQL TYPE IS CLOB_LOCATOR 964 4 CLOB Locator (1)
SQL TYPE IS DBCLOB_LOCATOR 968 4 DBCLOB Locator (1)
SQL TYPE IS RESULT_SET_LOCATOR 972 4 Result Set Locator
SQL TYPE IS TABLE LIKE table-name AS LOCATOR 976 4 Table Locator (1)
Note:
  1. Do not use this data type as a column type.
  2. n is the number of double-byte characters.

The following tables can be used to determine the PL/I data type that is equivalent to a given SQL data type.

Table 9. SQL data types mapped to PL/I declarations
SQL Data Type PL/I Equivalent Notes
SMALLINT BIN FIXED(15)
INTEGER BIN FIXED(31)
BIGINT BIN FIXED(63)
DECIMAL(p,s) DEC FIXED(p) or DEC FIXED(p,s) p = precision and s = scale; 1 <= p <= 31 and 0 <= s <= p
REAL or FLOAT(n) BIN FLOAT(p) or DEC FLOAT(m) 1 ≤ n ≤ 21, 1 ≤ p ≤ 21 and 1 ≤ m ≤ 6
DOUBLE PRECISION, DOUBLE, or FLOAT(n) BIN FLOAT(p) or DEC FLOAT(m) 22 ≤ n ≤ 53, 22 ≤ p ≤ 53 and 7 ≤ m ≤ 16
CHAR(n) CHAR(n) 1 ≤ n ≤ 32767
VARCHAR(n) CHAR(n) VAR  
GRAPHIC(n) GRAPHIC(n) n is a positive integer from 1 to 127 that refers to the number of double-byte characters, not to the number of bytes
VARGRAPHIC(n) GRAPHIC(n) VAR n is a positive integer that refers to the number of double-byte characters, not to the number of bytes; 1 ≤ n ≤ 2000
LONG VARGRAPHIC GRAPHIC(n) VAR n > 2000
DATE CHAR(n) n must be at least 10
TIME CHAR(n) n must be at least 8
TIMESTAMP CHAR(n) n must be at least 26
Table 10. SQL data types mapped to Meta PL/I declarations
SQL Data Type PL/I Equivalent Notes
Result set locator SQL TYPE IS RESULT_SET_LOCATOR Use this data type only for receiving result sets. Do not use this data type as a column type.
Table locator SQL TYPE IS TABLE LIKE table-name AS LOCATOR Use this data type only in a user-defined function or stored procedure to receive rows of a transition table. Do not use this data type as a column type.
BLOB locator SQL TYPE IS BLOB_LOCATOR Use this data type only to manipulate data in BLOB columns. Do not use this data type as a column type.
CLOB locator SQL TYPE IS CLOB_LOCATOR Use this data type only to manipulate data in CLOB columns. Do not use this data type as a column type.
DBCLOB locator SQL TYPE IS DBCLOB_LOCATOR Use this data type only to manipulate data in DBCLOB columns. Do not use this data type as a column type.
BLOB file reference SQL TYPE IS BLOB_FILE Use this data type only as a reference to a BLOB file. Do not use this data type as a column type.
CLOB file reference SQL TYPE IS CLOB_FILE Use this data type only as a reference to a CLOB file. Do not use this data type as a column type.
DBCLOB file reference SQL TYPE IS DBCLOB_FILE Use this data type only as a reference to a DBCLOB file. Do not use this data type as a column type.
BLOB(n) SQL TYPE IS BLOB(n) 1<n<2147483647
CLOB(n) SQL TYPE IS CLOB(n) 1<n<2147483647
DBCLOB(n) SQL TYPE IS DBCLOB(n) n is the number of double-byte characters. 1<n<1073741823
ROWID SQL TYPE IS ROWID  
XML AS SQL TYPE IS XML AS ... Used to describe an XML version of a BLOB, CLOB, DBCLOB, BLOB_FILE, CLOB_FILE, or DBCLOB_FILE 

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