Updating a specific row in sql rejection stories dating
I think the best way is to this by triggers, but how ?
this one doesnt work create trigger xy on table test for update, delete if lock=1 then rollback Rafa...
So, we can create a query with the following update statement: UPDATE “Employees”, SET, and then assign the value of the string “Stella” to the “first name” column, the string “Parkinson” to the “last name” column, the 31 of December 1990 to “birth date”, and “F” to “gender”.
The condition here is to have an employee number that equals John Smith’s number, 999901.
Remember, you should be careful when using this command because once you execute COMMIT, you cannot reverse any change!
So, after running ROLLBACK, where will we go back to? We see the information we had in the “Departments Duplicate” table at the beginning of this post.
In a nutshell, these are the SQL rules regarding transaction control.
We must be very careful when using COMMIT and ROLLBACK – in other words, when we are changing the state of our data set.
On the right-hand side, scroll down to get to the box that says, “Safe Updates”.Please note that it will be very hard to practice these statements unless we switch off the following feature of Workbench.We can expand the Edit tab from the Main Menu and opt for “Preferences”.Nevertheless, nothing would have happened – the statement would have worked, affecting 0 rows, because the data table doesn’t contain an employee with such a number at the moment of the query’s execution.
Stay focused for another interesting feature we will discuss next.
Before reading this post you may want to get familiar with our post about SQL INSERT Statement.