What are the difference between local table and global table?

Hi,
A local temporary table exists only for the duration of a
connection or, if defined inside a compound statement, for
the duration of the compound statement.

A global temporary table remains in the database
permanently, but the rows exist only within a given
connection. When connection is closed, the data in the
global temporary table disappears. However, the table
definition remains with the database for access when
database is opened next time.

The SQL standard, which defines how the term "GLOBAL TEMPORARY TABLE" is interpreted, allows for either a LOCAL or GLOBAL scope. This would allow for either a user specific table (LOCAL) or everyone (GLOBAL). Oracle implements only the GLOBAL version.

The data you put into an Oracle Temporary table is specific to your session. That is, only you can see your data even if there are 100 users all using the same table, and your data is deleted from the table when you disconnect (or when you commit the current transaction) depending upon table settings.

Contrast this with MS SQL-Server, where temporary tables are local. If you create one, no one besides you knows that your temporary table exists. In Oracle, creating the temporary table allows everyone (well everyone with access to your schema) to see the table. When you log out of your session, the SQL-Server table is deleted and will need to be recreated for the next session. In Oracle, the temporary table is now a permanent part of your schema, even if the data isn't.

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Gaurish Kumar17y ago

Accepted answer

Kirtan Patel17y ago
The SQL standard, which defines how the term "GLOBAL TEMPORARY TABLE" is interpreted, allows for either a LOCAL or GLOBAL scope. This would allow for either a user specific table (LOCAL) or everyone (GLOBAL). Oracle implements only the GLOBAL version.

The data you put into an Oracle Temporary table is specific to your session. That is, only you can see your data even if there are 100 users all using the same table, and your data is deleted from the table when you disconnect (or when you commit the current transaction) depending upon table settings.

Contrast this with MS SQL-Server, where temporary tables are local. If you create one, no one besides you knows that your temporary table exists. In Oracle, creating the temporary table allows everyone (well everyone with access to your schema) to see the table. When you log out of your session, the SQL-Server table is deleted and will need to be recreated for the next session. In Oracle, the temporary table is now a permanent part of your schema, even if the data isn't.

check "Do you like this answer" if it helps you :)
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