How do I create a materialized view log?

How do I create a materialized view log?

CREATE MATERIALIZED VIEW LOG ON tableName [WITH [PRIMARY KEY][,ROWID]|[ROWID][,PRIMARY KEY] [(columnName[,…])]] List of columns for which changes will be recorded in the log. Use the WITH clause to indicate the keys and columns for which changes will be recorded in the materialized view log.

Why materialized view log is created?

When DML changes are made to master table data, Oracle Database stores rows describing those changes in the materialized view log and then uses the materialized view log to refresh materialized views based on the master table. This process is called incremental or fast refresh.

What is Mview log?

In an Oracle database, a materialized view log is a table associated with the master table of a materialized view. When master table data undergoes DML changes (such as INSERT, UPDATE, or DELETE), the Oracle database stores rows describing those changes in the materialized view log.

Where can I find Mview logs?

Use [dba_|all_|user_]mview_logs . dba_mview_logs will show all the materialized view logs in the database but not everyone will have access to the dba_ views. You probably need create any dictionary . all_mview_logs will show you all the materialized view logs that you have access to.

How do I create a materialized view in Oracle?

Create a materialized view to perform the aggregation in advance, making sure you specify the ENABLE QUERY REWRITE clause. CREATE MATERIALIZED VIEW emp_aggr_mv BUILD IMMEDIATE REFRESH FORCE ON DEMAND ENABLE QUERY REWRITE AS SELECT deptno, SUM(sal) AS sal_by_dept FROM emp GROUP BY deptno; EXEC DBMS_STATS.

How do you automate a materialized view refresh?

Set the initialization parameters and bounce the database. Create the materialized view table. Here, we specify that the materialized view will be refreshed every two hours with the refresh fast option. Instead of using DBMS_MVIEW, you can automatically refresh the MVIEW (Snapshot) using Oracle DBMS_JOB Management.

How do I drop a Mlog table?

To drop a materialized view log, you must have the privileges needed to drop a table. Specify the schema containing the materialized view log and its master table. If you omit schema , then Oracle Database assumes the materialized view log and master table are in your own schema.

What is Oracle Mview?

A materialized view is a database object that contains the results of a query. The FROM clause of the query can name tables, views, and other materialized views. Collectively these objects are called master tables (a replication term) or detail tables (a data warehousing term).

Does materialized view store data?

A materialized view is a pre-computed data set derived from a query specification (the SELECT in the view definition) and stored for later use. Because the data is pre-computed, querying a materialized view is faster than executing a query against the base table of the view.

Can we create materialized view on a view?

Creating a materialized view requires CREATE MATERIALIZED VIEW privilege on the schema, and SELECT privilege on the base table. For more information about privileges and materialized views, see Privileges on a Materialized View’s Schema.

How do I grant a materialized view privilege?

To create a materialized view in another user’s schema:

1. You must have the CREATE ANY MATERIALIZED VIEW system privilege.
2. The owner of the materialized view must have the CREATE TABLE system privilege.

How can create materialized view in SQL Server with example?

Materialized views in Microsoft SQL Server

1. select p. ProductID, sum(t.
2. from Production. TransactionHistory t inner join Production.
3. select p. ProductID, sum(t.
4. from Production. TransactionHistory t inner join Production.
5. create unique clustered index TotalCostQuantityByProduct on v_TotalCostQuantityByProduct (ProductID)

Why are all MView logs created with 1 in the end of file name?

Any idea why all mview logs names were created with 1 in the end of file name… Because you only have one MV log on those tables. If you create a second MV log its name will end with ‘2’ and so on. Notice that you NEVER specify the name of the log table to create; you only specify the name of the table to create it on.

Can you create a materialized view log for a table?

You cannot create a materialized view log for a table in the schema of the user SYS. Specify the name of the master table for which the materialized view log is to be created. Restriction on Master Tables of Materialized View Logs You cannot create a materialized view log for a temporary table or for a view.

What does the create Materialized View statement do?

Use the CREATE MATERIALIZED VIEW statement to create a materialized view. A materialized view is a database object that contains the results of a query. The FROM clause of the query can name tables, views, and other materialized views. Collectively these objects are called master tables (a replication term)…

Can a nocache affect a materialized view log?

NOCACHE has no effect on materialized view logs for which you specify KEEP in the storage_clause. The parallel_clause lets you indicate whether parallel operations will be supported for the materialized view log. For complete information on this clause, please refer to parallel_clause in the documentation on CREATE TABLE.