0705_oracle sequence
-sequence sequnece
User_sequneces
Increment by 2-step size
Start with 2-starting value
Maxvalue 10-maximum 2 4 6 8 10
Nomaxvalue
Minvalue 2 minimum
Nominvalue
Cycle cycle
Nocycle
Cache 2 cach
Nocache
Order sorting
Noorder
1 3 5 7 15
Create sequnece seq1 start with 1 increment by 2 maxvalue 15 nocycle
Citation sequence
Current value sequence name. currval
The next value sequence name. Nextval
Create sequence seq3 start with 1 increment by 2 maxvalue 7 cycle
Create sequence seq3 start with 1 increment by 2 maxvalue 6 cycle nocache
Create sequence seq3 start with 3 increment by 2 maxvalue 6
Minvalue 2 cycle nocache
Cache 5
1 2 3 4 5
1 2 3 4 5 6 7 8 9 10 11
-modify sequence properties
New value of ALTER SEQUENCE xx sequence attribute
-temporary watch
Shopping cart-TABLE
(1) transaction end commit rollback
(2) end of session exit
Create global temporary table gwc (price number (4), name varchar2 (20))-transactions
Create global temporary table gwc (price number (4), name varchar2 (20)) on commit preserve rows
-
Constraint constraint
Maintain the integrity of the data
Delete constraint
SQL > ALTER TABLE nn1 DROP CONSTRAINT SYS_C0011064
Five constraints
Non-empty constraint
Unique constraint
Primary key constraint
External constraint
Check constraints-Custom constraint
Non-null constraint-do not allow null values to be inserted
1muri-keyword-NOT NULL
2Murray-Type-C
3Murray-multiple non-empty constraints are allowed in a table
4Murray-non-null constraints will inherit
5Murray-combined column constraints are not supported
Unique constraint-duplicate values are not allowed to be inserted, except for null
1Murray-keyword UNIQUE
2Murray Mutual-Type U
3Murray-multiple unique constraints are allowed in a table
4Murray-the only constraint does not inherit
5Murray-support combinational column constraints
Primary key constraint-non-null + unique
1Murray-keyword primary key
2Murray Mutual-Type P
3Mutual-one primary key constraint for lard in a table
4Murray-constraints do not inherit
5Murray-support combinational column constraints
External constraint
