How to avoid duplicate ID When data entry ?

[desmondtan]

How to write the checking of databse to prevent the duplicate duplicate of certain ID ( such as Employee Number ) when user do the data entry in Windows form ?

[stustarz]

If you have an option of disallowing duplicate table entries in your database then use that - what database are you using? You could then use Try, Catch to catch any exception that may be thrown if you try to entre a dup record.

 

If not you could use a SELECT sql command with a WHERE clause of the ID number you want to check for, if the sql select returns a record then the ID is already there if not then it is ok to insert data.

 

Stuart

[basesuck]

It is better to use the datatype uniqueidentifier in SQL-Server.

with this as primary key you can guarantee that this is key only exists one in the world.

[desmondtan]

Can Weuse Try....catch...End try to catch the duplicate ID when updating ? What exception should use ?

[a_jam_sandwich]

Send the error number to console and check there I think it is 5 though

 

Andy

[hemenkap]

ok suppose you dont want two ppl to have the same code name then what you can do is this

 

dim adr() as DataRow = Dataset.Tables("TableName").Select("EmpCode = '" & CODE & "'")

if adr.length = 0 Then

' the code to allow him to enter the value in db

Else

' sorry buddy value exists

End if