Disabling Table Constraints to Load Data
When loading data into tables, you will sometimes have to disable the constraints on your tables. Suppose that you have truncated your tables and you are loading data into your tables from scratch. More than likely, your tables will have referential integrity constraints, such as foreign keys. Because the database will not let you insert a row of data in a table that references another table (if the referenced column does not exist in the other table), you may have to disable constraints to initially load your data. Of course, after the load is successful, you would want to enable the constraints.
SQL> SET ECHO OFF SQL> SET FEEDBACK OFF SQL> SET HEADING OFF SQL> SPOOL DISABLE.SQL SQL> SELECT 'ALTER TABLE ...
Get Sams Teach Yourself SQL in 21 Days, Fourth Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
