INITIAL

INITIAL in SQL is a clause in Oracle database systems used to define the initial extent size that is to be used for a database segment when an object in a tablespace is created. The extent size is set in bytes and can influence the performance of the system based on how it is managed.

Example

CREATE TABLE students
(
    id INT,
    name VARCHAR(50),
    credit_taken INT DEFAULT 0
)
TABLESPACE students_data
    DATAFILE 'students_data01.dbf'
    SIZE 25M AUTOEXTEND ON
    NEXT 50M MAXSIZE 250M
    LOGGING
    INITIAL 25M
    MINEXTENTS 1
    MAXEXTENTS 50
    NOCOMPRESS;

Output

Table STUDENTS created.

Explanation

The above example illustrates the use of the INITIAL clause in Oracle SQL when creating a new table students. This creates an initial extent of 25MB. Extents are the smallest unit Oracle uses to manage database space. The INITIAL keyword indicates the initial amount of space that Oracle reserves when creating the object.

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