Constraints can be created at the same time as the table is created using

Constraints can be created at the same time as the

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Constraints can be created at the same time as the table is created (using CREATE TABLE) or after the table has been created (using ALTER TABLE) Sequences: Automatically generates unique numbers. Is sharable object. (used by multiple users) Is typically used to create a primary key value. Save time to write application code to generate unique numbers. Speeds up the efficiency of accessing sequence values when cached in memory. Syntax: CREATE SEQUENCE sequence_name [INCREMENT BY n ] [START WITH n ] [{MAXVALUE n | NOMAXVALUE } ] [{MINVALUE n | NOMINVALUE } ]
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[{CYCLE | NOCYCLE } ] [{CACHE n | NOCACHE} ] Sequence name follows the same rule as the Table Name or Constraint Name (start with a letter, max length 30 characters). If INCREMENT BY is omitted, default is 1, negative n means decreasing. If START WITH is omitted, default is 1. MAXVALE/MINVALUE specifies the maximum/minimum value of the sequence. The default is NO for both. By default, no CYCLE. Oracle cache 20 values. Alter Sequence ALTER SEQUENCE sequence_name [INCREMENT BY n ] [{MAXVALUE n | NOMAXVALUE} ] [{MINVALUE n | NOMINVALUE} ] [{CYCLE | NOCYCLE} ] [{CACHE n | NOCACHE} ]
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  • Fall '14
  • Foreign key, Constraint, data integrity

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