What is ROWID in Oracle?

The ROWID is a unique database-wide physical address for every row on every table. Once assigned (when the row is first inserted into the database), it never changes until the row is deleted or the table is dropped.

The ROWID consists of the following three components, the combination of which uniquely identifies the physical storage location of the row.

* Oracle database file number, which contains the block with the rows
* Oracle block address, which contains the row
* The row within the block (because each block can hold many rows)

The ROWID is used internally in indexes as a quick means of retrieving rows with a particular key value. Application developers also use it in SQL statements as a quick way to access a row once they know the ROWID

Partitioning in Oracle

Partitioning enables tables and indexes or index-organized tables to be subdivided into smaller manageable pieces and these each small piece is called a partition. From an Application Development perspective, there is no difference between a partitioned and a non-partitioned table. The application need not be modified to access a partitioned table if that application was initially written on a non partitioned tables.

Oracle introduced partitioning like Range Partitioning, Hash Partitioning, Composite Partitioning, List Partitioning,etc. Each method of partitioning has its own advantages and disadvantages and the decision which one to use will depend on the data and type of application. Also one can MODIFY, RENAME, MOVE, ADD, DROP, TRUNCATE, SPLIT partitions.

Advantages of using Partition’s in Table

1. Smaller and more manageable pieces of data (Partitions)

2. Reduced recovery time

3. Failure impact is less

4. Import / Export can be done at the Partition Level.

5. Faster access of data

6. Partitions work independent of the other partitions.

7. Very easy to use