Index (B-tree)

B-tree Index B-tree stands for Balanced Tree in RDBMS. It is commonly used in database and filesystem.The B-tree enables the database to find a leaf node quickly. It is a good example of a data structure for external memory. Telephone directory, library are the best example of B-tree index.   Why do we use B-tree? keeps keys in […]

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IOT Index IOT stands for Index Organised Table in oracle database.The idea behind an IOT is simple. You hold all the data for the table in the ordered structure of an index. Why do we use IOT? An IOT has the structure of an index and stores all the columns of the row, accesses via […]

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Index In Oracle

We are living on the planet with the seven billion population.Each and every human being’s have some information. Data is an important factor in the business’s world.  Every day in business’s operation we deal with data. It can be structure and un-structure data. All the report of business prepare with the help of data. We take a […]

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Scenario 1 – Recover a Member of a Multiplexed Online Redo Log Group

Please follow the below steps. Steps : 1. Shutdown immediate; 2. Physically remove redo log member(no redo log group) by using OS level command. 3. Startup; 4. SELECT GROUP#, STATUS, MEMBER FROM v$LOGFILE WHERE STATUS=’INVALID’; 5. Check alert log file. Steps for Recovery : 1. Drop the damaged member ALTER DATABASE DROP LOGFILE MEMBER ‘D:\app\admin\oradata\orcl\REDO01.LOG’; […]

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How to make a table read only in Oracle

Oracle 11g allows tables to be marked as read-only using the ALTER TABLE command.

Let’s create a table and make it read-only.

Any DML statements that affect the table data results in an ORA-12081 error message.

DML and DDL operations return to normal once the table is switched back to read-write mode. […]

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