Static SQL applications
For most Db2 users, static SQL provides a straightforward, efficient path to Db2 data.
The source form of a static SQL statement is embedded within an application program that is written in a traditional programming language such as C. The statement is prepared before the program is executed, and the operational form of the statement persists beyond the execution of the program. You can use static SQL when you know before run time what SQL statements your application needs to run.
When you use static SQL, you cannot change the form of SQL statements unless you make changes to the program. However, you can increase the flexibility of those statements by using host variables. Using static SQL and host variables is more secure than using dynamic SQL.
Example
For example, assume that you are coding static SQL in a COBOL program. The following UPDATE statement can update the salary of any employee. When you write your program, you know that salaries must be updated, but you do not know until run time whose salaries should be updated, and by how much.
01 IOAREA.
02 EMPID PIC X(06).
02 NEW-SALARY PIC S9(7)V9(2) COMP-3.
⋮ (Other declarations)
READ CARDIN RECORD INTO IOAREA
AT END MOVE 'N' TO INPUT-SWITCH.
⋮ (Other COBOL statements)
EXEC SQL
UPDATE EMP
SET SALARY = :NEW-SALARY
WHERE EMPNO = :EMPID
END-EXEC.
The UPDATE statement does not change, nor does its basic structure, but the input can change the results of the UPDATE statement.
Basic SQL coding concepts apply to traditional programming languages: C, C++, COBOL, Fortran, PL/I, and Assembler.
Suppose that you are writing an application program to access data in a Db2 database. When your program executes an SQL statement, the program needs to communicate with Db2. When Db2 finishes processing an SQL statement, Db2 sends back a return code, called the SQL return code. Your program should test the return code to examine the results of the operation.
Unique instructions and details apply to each language.