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The PRINT statement is used inside a procedure to store the content
of user-defined strings, local variables, parameters, or built-in variables in
the message buffer for display by ISQL or an application program.
Procedures only
PRINT {'Constant'
:LocalVariable
:Parameter
::Built-inVariable};
- Constant
is a string literal.
- LocalVariable
is a local variable declared within the procedure.
Types and sizes are the same as for column definitions, except you
cannot specify a LONG data type.
- Parameter
is a parameter declared within the procedure.
- Built-inVariable
is one of the following built-in variables used for error handling:
::sqlcode
::sqlerrd2
::sqlwarn0
::sqlwarn1
::sqlwarn2
::sqlwarn6
::activexact
The first six of these have the same meaning that they have
as fields in the SQLCA in application programs. Note that in procedures,
sqlerrd2 returns the number of rows processed for all host languages.
However, in application programs, sqlerrd3 is used in COBOL, Fortran,
and Pascal, while sqlerr2 is used in C. ::activexact indicates whether
a transaction is in progress or not. For additional information,
refer to the application programming guides and to the chapter
"Constraints, Procedures, and Rules."
The results of any PRINT statements issued during the
execution of a procedure are placed in the ALLBASE/SQL message
buffer, and may be displayed like other messages. In an application
program, they can be retrieved with SQLEXPLAIN upon exiting the
procedure.
The message number 5000 is used for all PRINT
statements.
Anyone can issue the PRINT statement.
CREATE PROCEDURE Process15 (PartNumber CHAR (16) NOT NULL) AS
BEGIN
DECLARE PartName CHAR(30);
SELECT PartName INTO :PartName
FROM PurchDB.Parts
WHERE PartNumber = :PartNumber;
IF ::sqlcode <> 0 THEN
PRINT 'Row not retrieved. Error code:';
PRINT ::sqlcode;
ELSE
PRINT :PartName;
ENDIF;
END;
When an application program calls a procedure, you can include PRINT
statements in the procedure for later retrieval by the application:
IF ::sqlcode = 100 THEN
PRINT 'Row was not found';
ELSE
PRINT 'Error in SELECT statement';
ELSEIF ::sqlcode=0 THEN
PRINT :PartName;
ENDIF;
On returning from the procedure, use SQLEXPLAIN in a loop to extract all the
messages generated by PRINT during the operation of the procedure.
In C:
while (sqlcode != 0 || sqlwarn[0]=='W') {
EXEC SQL SQLEXPLAIN :SQLMessage;
printf("%s\n",SQLMessage);
}
In COBOL:
IF SQLCODE IS NOT ZERO OR SQLWARN0 = "W"
PERFORM M100-DISPLAY-MESSAGE
UNTIL SQLCODE IS ZERO AND SQLWARN0 = "W".
.
.
.
M100-DISPLAY-MESSAGE.
EXEC SQL SQLEXPLAIN :SQLMESSAGE END-EXEC.
DISPLAY SQLMESSAGE.
M100-EXIT.
EXIT.
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