A. To build the table
CREATE TABLE 表
(
ID INTEGER not null,
NAME NVARCHAR2(256),
DEL_FLG int
,CONSTRAINT "PF_表" PRIMARY KEY ("ID")
)
II. Creating a Sequence
CREATE SEQUENCE Table _ID
the INCREMENT BY. 1 - a designated interval between the sequence number, this value may be positive or negative integers, but not to zero. Ascending sequence. When this clause is omitted, the default value of 1
START WITH 1 - specifies a sequence number generated first. When ascending, the sequence may begin with a value larger than the minimum value, the minimum value is the default sequence. For values in descending order, the sequence may be less than the maximum starts, the maximum default value of the sequence.
NOMAXVALUE - Specify a maximum of 1027 for the ascending, descending specified maximum value -1.
ORDER
NOCYCLE
CACHE 10;
III. Creating Triggers
CREATE OR REPLACE TRIGGER trigger name
BEFORE INSERT ON table
the FOR EACH the ROW
the BEGIN
the SELECT yqjyMaintain_ID.nextval the INTO: the FROM NEW.ID the DUAL; - trigger conditions (sql statement)
the END trigger name;
Trigger name: The name of the trigger object. As the trigger is a database automatically, so the name is just a name, there is no real purpose.
Trigger Time: when specified trigger execution, the desirable value:
before: indicates that the trigger action is performed before database;
After: mean do it after the database operation.
Triggering Event: specify which database trigger action will trigger this:
INSERT: insert database triggers this flip-flop;
Update: database modifications will trigger the trigger;
the Delete: Delete the database triggers this trigger.
Table Name: Table database triggers located.
for each row: execute once for each row in the table trigger. Without this option, only be performed once for the entire table.
Triggers can achieve the following functions:
Function :
1, to allow / restrict modification to the table
2, generated automatically derived columns, such as the self-energizing field
3, force data consistency
. 4, auditing and logging
5, to prevent invalid transaction
6, enable complex business logic