[Oracle] Sequence object usage, oraclesequence object

[Oracle] Sequence object usage, oraclesequence object
**************************************** ********************************* *** Original article: blog.csdn.net/clark_xu Xu changliang's column**************************************** ********************************

 

Sequence: oracle can generate primary keys through sequences.

1. Create a sequence

Create table Foo (

Foo_id number (11 ),

Foo_value varchar2 (50 ),

Constraint FOO_PK primary key (foo_id)

)

Create sequence DDL

Create sequence name

[Start with value (10000)]

[Increment by value]

Delete sequence DDL

Drop sequence name

2. view the sequence

Obtain the current sequence value through the pseudo-column currval

Use the pseudo column nextval to obtain the next value of the sequence value.

Select seq_foo.nextval from dual;

Select seq_foo.currval from dual;

3. Use sequence as the primary key

Insert into foo (foo_id, foo_value) values (seq. foo. nextval, 'clark ');