By default, a database sequence has the INCREMENT BY attribute as 1, which creates an ascending sequence that increments the integer values by 1. By default a new sequence does not have a minimum/maximum limit for the sequence of integers, does not cycle values after reaching its minimum/maximum value, and does not guarantee that sequence numbers are generated in the order of request. The CREATE SEQUENCE statement supports several clauses to customize a sequence. Use the CREATE SEQUENCE statement to create an Oracle Database Sequence. GRANT CREATE ANY SEQUENCE, ALTER ANY SEQUENCE, DROP ANY SEQUENCE, SELECT ANY SEQUENCE TO seq_user Create a sequenceĬonnect as the seq_user user to create a sequence. The following statement grants the seq_user user the privilege to create/alter/drop a sequence in any schema. To allow a user to create a Sequence in any schema, grant the CREATE ANY SEQUENCE privilege. The CREATE SEQUENCE privilege only lets a user create a Sequence in its own schema. The CREATE SEQUENCE privilege may also be grant separately to an existing user: GRANT CONNECT, RESOURCE, CREATE SESSION to seq_user Grant the RESOURCE privilege that lets a user create a sequence in its own schema, in addition to creating other database objects such as a table and a PL/SQL procedure. Grant privileges to the user to connect and create a session. Create a user and grant privilegesĬonnect as the ADMIN user, and create a user ( seq_user as example) with the CREATE USER command that we’ll use to create a Sequence.
As a preliminary setup, install Toad for Oracle, create an instance of Oracle Autonomous Database 19c (or other), and connect to the database instance, all of which is discussed in How to download Toad for Oracle. This article is based on Oracle Database 19c for earlier versions, such as 12c, some differences may exist. A Sequence can be ascending or descending.
A Sequence’s values can be accessed using the NEXTVAL, and CURRVAL pseudo-columns. This is in contrast to the AUTO_INCREMENT attribute in MySQL which is limited in scope as it only generates a sequence of integers that increment by 1, with no provision to set upper or lower limits, or cache values.Īn Oracle Sequence is a database object, just like a table or view, that represents a sequence of integers that can be used by any table or view in the global database namespace. Oracle Database provides Oracle Sequence for creating a sequence of integers, with additional features such as cache, upper/lower limits, and flexibility that lets a user create a customizable database sequence of integers. It is often necessary to assign integer column values that are in sequence across different rows of data in a relational database.
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