Informix-ESQL/C Programmer's Manual Chapter 2: INFORMIX-ESQL/C Data Types

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The BOOLEAN Data Type ESQL/C uses the boolean data type to support the SQL BOOLEAN data type. For a complete description of the SQL BOOLEAN data type, see the Informix Guide to SQL: Reference. This section describes how to manipulate the ESQL/C boolean data type. You can declare a boolean host variable as follows: EXEC SQL BEGIN DECLARE SECTION; boolean flag; EXEC SQL BEGIN DECLARE SECTION; In an ESQL/C program, the following values are the only valid values that you can assign to boolean host variables: Boolean Value Representation TRUE '\1' FALSE '\0' NULL Use the rsetnull() function with the CBOOLTYPE as the first argument If you want to assign the character representations of 'T' or 'F' to a BOOLEAN column, you must declare a fixchar host variable and initialize it to the desired character value. Use this host variable in an SQL statement such as the INSERT or UPDATE statement. The database server converts the fixchar value to the appropriate BOOLEAN value. The following code fragment inserts two values into a BOOLEAN column called bool_col in the table2 table: EXEC SQL BEGIN DECLARE SECTION; boolean flag; fixchar my_boolflag; int id; EXEC SQL END DECLARE SECTION; id = 1; flag = '\0'; /* valid boolean assignment to FALSE */ EXEC SQL insert into table2 values (:id, :flag); /* inserts FALSE */ id = 2; rsetnull(CBOOLTYPE, (char *) &flag); /* valid BOOLEAN assignment to NULL */ EXEC SQL insert into table2 values (:id, :flag); /* inserts NULL */ id = 3; my_boolflag = 'T' /* valid character assignment to TRUE */ EXEC SQL insert into table2 values (:id, :my_boolflag); /* inserts TRUE */