Table partitioning

simon87

I currently have some tables with data and need to partition. Can be a partition to an existing table with lots of data?

How do I manipulate a partition? For example: In the query, how would he know on which partition find?, in which partition delete? What partition insert?

Thanks

L-MachineGun

Learn about partitioning in the fine Oracle® Database VLDB and Partitioning Guide

To convert non-partitioned table to partitioned table, use DBMS_REDEFINITION

simon87

Ok, thank you. Greetings

Keen2Learn

For creating partitions, it is better to create partitioned tables first and the copy data from non-partitioned table to partitioned table.

About search from query, it depends on what kind of partitioning you are using and while searching, partition key should be referenced to improve query performance.

You can select from specific partition by below:

select * from tablename partition (partitioname);

Similarly, you can delete from specific partition by mentioning partition clause.

Insert is based on what kind of partitioning you using. Based on insert values, it will insert into specific partition for which data is true.

Thank you.

Billy Verreynne

Keen2Learn wrote:

You can select from specific partition by below:

select * from tablename partition (partitioname);

Similarly, you can delete from specific partition by mentioning partition clause.

Not a sound approach as it requires the SQL statement to know the partitioning scheme of the table, and the name of the partition. It also forces a literal (the partition name) to be used in the SQL, which requires a brand new SQL statement for the same query on a different partition.

In app developer terms, it means having to use dynamic SQL to string the relevant partition name into the SQL. It also means runtime bugs as if there is data for that query and you point it to the wrong partition in your code, no rows will be found.

Partitioning should be TRANSPARENT to the developer and database user. They should not need to know whether that table is partitioned, how it is partitioned, and what the name of the partition of interest is.

They should write STANDARD SQL, with bind variables, and the CBO should be able to determine the relevant partition or partitions to query, the vast majority of the time.