Compare value expressions. Relational operators are used in conditional expressions. See the table in the list of subtopics for a summary of the RDML relational operators.
1 – Table
Relational Value Operator ------------------------------------------------------------- EQ = True if the two value expressions are equal. NE <> True if the two value expressions are not equal. GT > True if the first value expression is greater than the second. GE >= True if the first value expression is greater than or equal to the second. LT < True if the first value expression is less than the second. LE <= True if the first value expression is less than or equal to the second. ------------------------------------------------------------- Note: In all cases, if either value expression is missing, the value of the condition is missing.
2 – Examples
The following programs demonstrate the use of the LE (less than or equal to) operator in a FOR statement. The programs create a record stream of all those employees who have an employee ID less than or equal to 00400. The programs then print the employee IDs from the records in the record stream.
2.1 – C Example
#include <stdio.h> DATABASE PERS = FILENAME "PERSONNEL"; main() { READY PERS; START_TRANSACTION READ_WRITE; FOR E IN EMPLOYEES WITH E.EMPLOYEE_ID LE "00400" printf ("%s\n", E.EMPLOYEE_ID); END_FOR; COMMIT; FINISH; }
2.2 – Pascal Example
program relation (input,output); DATABASE PERS = FILENAME 'PERSONNEL'; begin READY PERS; START_TRANSACTION READ_ONLY; FOR E IN EMPLOYEES WITH E.EMPLOYEE_ID LE '00400' writeln (E.EMPLOYEE_ID); END_FOR; COMMIT; FINISH; end.