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In today’s article, we will be learning how to creation of Index Organized Tables (IOT).
It stores all data in the B*Tree index structure. Therefore, it returns results very quickly when the data is queried.
DML performance is low because the data is sorted in each INSERT operation.
It is a schema object that contains frequently queried data using the column on the “Primary Key”. If there is no PRIMARY KEY, an error will be received when creating the table.
When creating a table, the word “ORGANIZATION INDEX” is created as follows.
1 2 3 4 5 6 7 8 9 10 | SQL> CREATE TABLE IOT_TABLE ( ID NUMBER, URUN_ADI VARCHAR2(20), ACIKLAMA VARCHAR2(400), CONSTRAINT ID_PK PRIMARY KEY (ID) ) ORGANIZATION INDEX; Table created. |
If we do not create an index table, the data is fetched in the order they were inserted.
This is done according to the ROWID of each row. This ROWID column is Pseudocolumn.
However, when the index table is created, data is kept according to the primary key every time it is added.
This is why the DML process is slow. Sorts all data in each insert.
