How do I get the login user and the machine address of the user that operates the current table in t

select top(1)* from table_name order by update_time desc

My idea is to find the result of the first place in descending order of modification time, isn't it?

With the words of the trigger.

create trigger.

on Table name.

for update

asselect * from table name where primary key = ?

create table t_a (id int not null, y varchar(20), other_id int);

create sequence seq_a_id

minvalue 1

maxvalue 9999999999;

create or replace trigger changefield_trigger before insert on t_a

This must be used before, not after.

for each row

beginselect seq_a_

intofrom dual;

end;-Test.

insert into t_a(y) values ('test1');

insert into t_a(y) values ('test2');

insert into t_a(y) values ('test3');

select * from t_a;

d x other_id

1 test1 1

2 test2 2

3 test3 3

In fact, it is a user, which is used directly. Don't select user into v user from dual.

create or replace trigger tr t1 uafter update on t1--- triggered when t1 is modified.

for each row

beginupdate t2 set col1 = ,col2=,..

where id = ;id is a key column and cannot be modified; or other associated conditions.

end;

after insert on ry_jbxx for each row

Here this table does not exist, of course it tells you that the table does not exist.

In this way, after insert on for each row, note that the tables that access other users are written like this.

Triggers are executed with the permissions of the owner of the table that defines those permissions, not the permissions of the user who caused the trigger to fire, and not the permissions of the user who created the trigger.

When a trigger references a table, it uses the group membership of the table creator to find a table that doesn't have the specified display owner's name. For example, if a trigger on user references table b, and the owner of table b is not specified, then table b must have been created by user 1, or user 1 must be a member of a group that is the owner of table b (directly or indirectly). If neither of these conditions is met, the trigger will fire with the message [Table not found].

In addition, user 1 must have permission to perform operations on the table specified in the trigger.

So we need user B to give user A the permission to operate the 'table b' table. (If there is an operation to add, delete, or modify the table 'Table B' of user B in the trigger on the 'Table A' table of user A, then user B needs to add, delete, and modify the table of 'Table B' of user A.)

Permissions: select, insert, update, delete

grant permission on tablename to username;

Note: The user using this statement must be the owner of the table.

For example, user user 1 is user in table a, and user 2 is user in table b

You need to log in to user 2 and grant permission on table b to user 1;

If it is triggered by a certain field, it should be possible.

But if you start this field again, it might be difficult, right?

Or add an if condition to determine that it is triggered when it is a certain value.

create trigger biufer_employees_department_id

before insert or updateof department_id

on employees

referencing old as old_valuenew as new_value

for each row

when (new_<>80 )

beginnew_ :=0;

end;This is self-triggered.

It's as simple as assigning a value to the field you want to assign a value to in the trigger

value;

This is a trigger that is in the same transaction and does not fire itself again.

create or replace trigger tr_name after

for insert or upedate on table_name

beginupdate table_name set column=value;

end tr_name;

This is the way to modify the table when you enter it, but in fact, the easiest way is to modify the table, create a default value, as soon as you enter the record, the field will be automatically assigned. No stored procedures at all. Isn't it too complicated?

The two elements of the table name and list are what you must know in advance, and if you have DBA permissions, you can look up the dictionary table.