Chapter 20. Native Dynamic SQL
Generally, PL/SQL applications perform a specific task and manipulate a static set of tables. For example, a stored procedure might accept a student ID and return the student's first and last names. In such a procedure, a SELECT statement is known in advance and is compiled as part of the procedure. Such SELECT statements are called static because they do not change from execution to execution.Now, consider a different type of PL/SQL application where SQL statements are built on the fly, based on a set of parameters specified at run-time. For example, an application might need to build various reports based on SQL statements where table and column names are not known in advance, or sorting and grouping of data is specified by a user requesting a report. Similarly, another application might need to create or drop tables or other database objects based on the action specified by a user at run-time. Because these SQL statements are generated on the fly and might change from time to time, they are called dynamic .PL/SQL has a feature called native dynamic SQL (dynamic SQL for short) that helps you build applications similar to those described above. The use of dynamic SQL makes such applications flexible, versatile, and concise because it eliminates the need for complicated programming approaches. In this chapter you will learn how to create and use dynamic SQL. |
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