SQL & PL/SQL :: Regular Table Or Materialized View - Clone Table Data In Another Database
Jul 19, 2010
There is a requirement to make a table data in a database (eg: HR database) available in another database (eg: EMP database), instead of accessing it using database link. In EMP database(where data needs to be cloned), data will only be queried and no write operation will be done. Data in remote database (eg: HR DATABASE) will be occassionally fully truncated and reinserted. The plan is to do a similar truncate and reinsert of data (from HR database) into EMP database monthly once using dbms scheduler job. So basically data in just one table needs to be cloned in another database.
Question: For this situation, is a regular table or Materialized view the right choice to clone the table in EMP database and why? The table in HR database (remote database) is not very big.
I have a materialized view "pro_mview",I am trying to refresh the MVIEW by using the following statement.
But I am getting the below error.
* Error at line 1: ORA-12008: error in materialized view refresh path ORA-00942: table or view does not exist ORA-06512: at "SYS.DBMS_SNAPSHOT", line 2256 ORA-06512: at "SYS.DBMS_SNAPSHOT", line 2462 ORA-06512: at "SYS.DBMS_SNAPSHOT", line 2431 ORA-06512: at line 1
I am able to fetch the data from that materialized view(pro_mview).
CREATE MATERIALIZED VIEW MV_NESTED_DATA NOCACHE LOGGING NOCOMPRESS NOPARALLEL BUILD IMMEDIATE USING NO INDEX REFRESH COMPLETE ON DEMAND START WITH ROUND(SYSDATE) NEXT ROUND(SYSDATE) + 1 WITH ROWID AS select NESTED_TABLE_FIELD from MY_TABLE@Y_DB_LINK;
where NESTED_TABLE_FIELD is a nested table stored as T_NESTED_TABLE
And I get the error: ORA-12014: table 'T_NESTED_TABLE' does not contain a primary key constraint
Why should it if I try to create a MV with "WITH ROWID" refresh option and not "WITH PRIMARY KEY" one?
We are in the process of migrating our databases to a hosting provider (10g Sun -> 11g LINUX.) A (former) data architect at our business had this (nightmare) situation implemented:
- have materialized views created - after creation of mat views(and associated tables), add additional audit columns to the table that are populated by triggers, not by the MV. All data is important.
In order to get all of the data to the hosting provider, we data pump export the full schemas (which include the associated MV tables), have the provider DBA's import (all the materialized views failed on import, but the associated MV tables were created/populated), and I'm now attempting to fix the MV code to get them recreated. Over 100 MV's, most of which have these extra audit columns, and a number of the remote master/source tables do not have primary keys so using the by rowid option. An edited example (object names changed to protect the innocent) - using CAST to include the audit columns:
CREATE MATERIALIZED VIEW SCHEMA1.ACCOUNT ON PREBUILT TABLE USING INDEX PCTFREE 10 INITRANS 2 MAXTRANS 255 STORAGE(INITIAL 512K NEXT 512K PCTINCREASE 0 BUFFER_POOL DEFAULT) TABLESPACE S_TS_01_INDX REFRESH FAST ON DEMAND WITH ROWID USING DEFAULT LOCAL ROLLBACK SEGMENT DISABLE QUERY REWRITE AS SELECT ACCOUNT.GROUP_ID GROUP_ID ... ... cast(null as date) CREATE_PROCESS_DATE, cast(null as varchar2(20 CHAR)) CREATE_PROCESS_ID FROM SCHEMA2.ACCOUNT@REMINSTANCE.WORLD ACCOUNT /
ORA-12058: materialized view cannot use prebuilt table
IF remove "with rowid", get error that cannot create because no primary key on source table.
Online options seem to be (1) do not use prebuilt table (in which case we'd lose the additional audit data) or (2) add a primary key on the master table (we're not in a timeline to make & test changes to various production source tables.)
Other thoughts on how to get this data migrated/populated? This needs to be a lift and drop as much as possible - any type of rewrite/restructuring is out of the question.
In Oracle 10gR2.If a materialized view uses a database link for the query in order to create a snapshot of data on a remote instance, does the name of the database link have to be an entry in the tnsnames.ora file?
The following link suggests not, but is not version specific: Materialized View - Oracle Wiki FAQ
However, the following 11g documentation suggests that the database link name must be the same as the global name of the target database.URL.. I can't any info specific to 10gR2.
We have three instances. Our application metadata is stored in a schema in B.METADATA. There is a shell schema (B.METADATASHLL) that provides access to the tables to remote applications.
On instance A, we have a shell schema (A.METADATASHLL) that creates materialized views as follows: CREATE DATABASE LINK METADATA_PRIME CONNECT TO metadatashll IDENTIFIED BY password USING 'B';
Our materialized view is created using the query SELECT * FROM METADATA.APPLICATIONS@METADATA_PRIME WHERE Application = 'A';
The query works, but the materialized view does not.I'm being told that the database link has to be named B as follows
CREATE DATABASE LINK B CONNECT TO metadatashll IDENTIFIED BY password USING 'B';
Which means that I can only have one public link to instance B, and I'm in a pickle if I create a second application (which I have) using the same model).
We have 2 production (OLTP) database( DB1 (18GB) and DB2 (200GB) ) on a server out of which DB2 database has almost 20 Materalized Views all (REFRESH FORCE ..ON DEMAND).
I have already informed the client that this is not the OLAP database where you are going to make use of the M Views for reporting purpose. However currently the client does not have any alternative.
Breif details :- Out of 20 M Views 3 refresh once a week and where as the rest refresh every night daily.
We are currently testing a new website for which we had to re-schedule all M Views from their Old timings to New Timings i.e. Daily Basis.
But post re-scheduling the database performance was badly degarded as the database was too slow also the number of archives increasted to 300GB which was earlier 100 GB.To resolve the issue , we had to go back to the old timings and the database is currently working fine.
Requirement :-Client is looking out for an alternative solution as he needs to once again change the M View refresh time i.e. Daily Refresh.We already have 2 Oracle Instance on the server
1. Can i create another database ( sayTESTDB2 ) in no archivelog mode and create a db link to reduce the load on the server ? 2. If Yes .. Then is there any relavent link /example or Metalink Note ID for the same?? 3. What all parameters do i need to consider while creating a DB Link ? 3. Out of 32 GB RAM , I have given 4GB and 8GB sga_max to DB1 and DB2 Respectively . Also the cpu utilization is normally 50-%60%.
Since currently we do not have any Licence for other server .. Can i make use of the same server ( i.e. creating 3 rd Oracle Instance )?
Since the main intention of this activity is reduce the load from the DB2 onto TESTDB when the daily refresh has set once again
I have a view which is taking long time to get back results and this view is being used in various user queries. I noticed that the SQL of the view access some tables, data of them changes rarely. So it makes sense to retrieve that data in a materialized view and somehow re-use it.
My question is how can I use the materialized view and it's data from a query.
How I can create a Materialized View without having any data in it.
I create a Materialialized View based on a View.
CREATE MATERIALIZED VIEW test_mv REFRESH FORCE ON DEMAND AS SELECT * FROM test_view
In the above case the data fetched by the view test_view gets stored in the Materialized View test_mv. Suppose I want materialized view test_mv to get created with all the columns of test_view but not the data. I will refresh the materialized view test_mv later for data as and when required.
What shall I do for immidiate formation of materialized view test_mv without data.
I have created a materialized view and also a normal View, which has 3 tables used in both the views, when inserted new records it reflects in a normal view but when i select the materialized view i cant see the updated data.
here is the materialized view i created;
CREATE MATERIALIZED VIEW pct_sales_materialized BUILD IMMEDIATE REFRESH ON DEMAND ENABLE QUERY REWRITE AS SELECT A.DEP_NAME,B.EMP_ID,C.EMP_NAME FROM department_head A,department_child B,emp_detail C WHERE A.DEP_ID = B.DEP_ID AND B.EMP_ID = C.EMP_ID
I have a PL/SQL procedure which gathers data from multiple places as well as calculates some data. I want to store all this in a materialized view.So, I created an object type (I've shortened the definitions):
CREATE OR REPLACE TYPE mf_record_type AS OBJECT (identifier VARCHAR2(6), name VARCHAR2(100));
Then created the table type of the object:
CREATE OR REPLACE TYPE mf_table_type IS TABLE OF mf_record_type;
Then in the stored procedure defined a variable of the table type:
I have a table testing_mview on 10g which do not have any primary key. I have created MV log for it:
CREATE MATERIALIZED VIEW LOG ON testing_mview WITH ROWID; Materialized view log created.
My requirement is 1) if there is an UPDATE/DELETE/INSERT on testing_mview, it should be writen to MATERIALIZED VIEW LOG (this has been achieved) 2) Materialized view testing_mview1 of 11g on server 10.1.4.32 should pull these changes on a scheduled basis ( I have created the database link ORCL10R2 here from 11g to 10 g)
On 11g: SQL> create database link ORCL10R2 connect to omig identified by pswd using '(DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = 10.1.4.30)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = ICS3) ) )';
Database link created
SQL> create materialized view testing_mview1 REFRESH FAST with rowid as select * from testing_mview@ORCL10R2; create materialized view testing_mview1 REFRESH FAST with rowid as select * from testing_mview@ORCL10R2 * ERROR at line 1: ORA-04052: error occurred when looking up remote object SYS.DBMS_SNAPSHOT@ORCL10R2 ORA-00604: error occurred at recursive SQL level 2 ORA-06544: PL/SQL: internal error, arguments: , , , , , , ,  ORA-06553: PLS-801: internal error  ORA-02063: preceding 2 lines from ORCL10R2
is it possible to base a Materialized View on results returned from a stored procedure?If not, do you see any other way except of filling a table with data from the stored procedure and then basing the MV on it?
How can i load the data into a new table from view,when ever scheduler runs in the night, the data gets loaded in to a view and data coming from different tables and i should load that data every day and i dont want previous data again.The data should be loaded along with view .
I'm trying to create a function that simply returns the current database name (e.g: select db_unique_name FROM v$database ) from a function but when I compile it comes up with :
Error(9,5): PL/SQL: SQL Statement ignored Error(9,44): PL/SQL: ORA-00942: table or view does not exist
I am compiling and running this as the SYSTEM user and I do think that I need to set privledges/roles, etc to allow this (since I have read that using synonyms in functions/procedures requires permissions...but I cannot seem to find anything that tells me exactly what role/priveledge I need to grant/allow to let this happen.
base on performance it is better to retrieve data from view or mention the table names directly?
I have a select statement in from clause one of my table is view (which is having data collected from four tables) my question is whether performance of querry will be improved if i use directly all tables( four tables of a view) instead of a view