oracle delete temporary table

Oracle database system is a relational database system that is currently widely used. When applying Oracle database, it is sometimes necessary to create temporary tables for data operation and processing, but it is also extremely important to delete the temporary tables after use. Therefore, how to delete Oracle temporary tables is a knowledge point that must be mastered when using Oracle database.

In Oracle database, temporary tables are created using the CREATE GLOBAL TEMPORARY TABLE statement. Its characteristics are: the temporary table does not allocate storage space when it is created, and only allocates storage space when data is inserted into it for the first time. When the session ends, Oracle will automatically delete the temporary table and its data. Therefore, when using the Oracle database, temporary tables are often used to store session information or intermediate results.

The specific steps for Oracle to delete a temporary table are as follows:

1. Use the Drop statement to delete the temporary table

Using the Drop statement is the most common method for Oracle to delete a temporary table. Its format It is:

Drop Table table_name;

where table_name is the name of the temporary table that needs to be deleted.

It should be noted that the Delete statement cannot be used when Oracle deletes a temporary table, because the Delete statement can only delete the data in the table, but not the table itself. If you use the Delete statement, only the data in the temporary table will be deleted, but the temporary table itself will not be deleted. The temporary table will be automatically deleted after the current session ends. Therefore, using the Drop statement is the safest method.

2. Use the Truncate statement to delete the temporary table

You can also use the Truncate statement to delete the temporary table. The format is:

Truncate Table table_name;

where , table_name is the name of the temporary table that needs to be deleted.

The difference between the Truncate statement and the Drop statement is that the Truncate statement will only delete the data in the table, but not the table itself. Therefore, when using the Truncate statement to delete, you need to note that only the data in the temporary table can be deleted. The temporary table will be automatically deleted after the current session ends.

3. Exit the current session

In the Oracle database, the temporary table is only valid in the current session. When the session ends, the system will automatically delete the temporary table and its data. Therefore, when using the Oracle database, if you need to delete the temporary table, you can also delete the temporary table by exiting the current session. The specific steps are as follows:

In the SQLPLUS environment, use the Exit or Quit command to exit the current session, or click the "Close Session" button in the Oracle client to automatically delete all temporary tables created under the current session. .

Generally speaking, when using Oracle database, it is very important to delete temporary tables to avoid data confusion and space waste caused by temporary tables. When deleting a temporary table, you need to choose the correct deletion method, and consider Drop, Truncate, and exit the current session in order. At the same time, in order to ensure data security, deletion operations must be performed with caution to avoid deleting the wrong table by mistake.

Deleting temporary tables in Oracle database is one of the basic operations of Oracle database. If you want to better use Oracle database, you can also master other related skills and knowledge. Generally speaking, learning Oracle database technology requires continuous learning and mastering in order to use the Oracle database system more skillfully and effectively in practical applications.

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