Oracle copy table, temporary table, and view, oracle copy table ViewCreate a new_table table with the same structure as the old_table Table (no old_table Records)
Create table new_table
Copy a table to another table, view, and temporary table. create a new_table table with the same structure as an old_table table without the old_table record. create table new_table as
,sysdate, ' temperary table ');sql> INSERT INTO permernate values (1);Sql> commit;Sql> select * from Admin_work_area;Sql> select * from Permernate;A12) on COMMIT PRESERVE ROWS defines a method for creating a session-level temporary table.CREATE GLOBAL Temporary TABLE Admin_work_area(StartDate DATE,EndDate DATE,Class CH
establish a connection when the release connection is needed.The table created by the temporary table and the CREATE TABLE statement has the same physical engineering, but the temporary table differs from the normal
temporary table is created by a stored procedure or an application executed by multiple users at the same time, SQL Server must be able to differentiate the tables created by different users. Therefore, SQL Server adds a digital suffix to the table name of each local temporary tab
in the table is valid only for the current session or transaction.
To establish a method:
1 on COMMIT DELETE ROWS defines a method for establishing a transaction-level temporary table.
CREATE GLOBAL Temporary TABLE admin_work_area
(startdate date,
enddate date,
such as temporary stored procedures, temporary functions, and temporary objects are stored in tempdb. The temporary table with the # prefix is local, so it is accessible only in the current user session, and # #前缀的临时表是全局的, so all user sessions can be accessed.
Tags: how database connections usersThe difference between a temporary table and a table variable in SQL ServerFebruary 20, 2009 Friday 19:31When we use a table in a database, we often encounter two ways to use the table, namely, the use of
the instance. The name of the global temporary table is prefixed with "# #", which is visible to any user after it is created, and is deleted when all users referencing the table are disconnected.
Let's look at an example of creating a temporary table:
CREATE
max_heap_table_size and tmp_table_size.
A derived table is generally used in the from clause. For example:
select * from (select * from table) as t;
About temporary tables
When you work on a very large table, you may occasionally need to run many queries to obtain a small subset of a large amount of data, instead of r
When using tables in a database, we often encounter two ways to use tables: using temporary tables and table variables. In actual use, how can we flexibly use them in the stored procedure? Although they implement the same functions, in a stored procedure, how does one sometimes use temporary tables instead of table var
official manual:As indicated by the name, memory tables are stored in memory. they use Hash indexes by default, which makes them very fast, and very useful for creating temporary tables. however, when the server shuts down, all rows stored in memory tables are lost. the tablesThemselves continue to exist because their definitions are stored in. frm files on disk, but they are empty when the server restarts.
It can be seen that memory is indeed very f
application ends, you may also need to establish a connection when releasing the connection.
So what is a temporary table? In the create table, we can know that the temporary table and the table created with the create
In practical use, how can we flexibly use them in stored procedures, although they implement the function is basically the same, how can there be time in a stored procedure to use temporary tables instead of using table variables, sometimes to use table variables instead of using temporary tables?Temp TableA
)Temporary tables cannot store data permanently.
4)Temporary table data will not be backed up, restored, and no log information will be generated for its modifications.
5)Temporary tables do not have DML locks
DML locks are not acquired on the data of the temporary tables. T
establishes a connection to the database engine. An application can establish one or more connections to a database, and in addition, an application may establish a connection and never release it until the application is finished, or it may use the release connection when it is needed.
Tables created by temporary tables and CREATE TABLE statements have the same physical engineering, but
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