You should do this check in the database. Always, if you want it to be true of the data.
I'm not sure what you consider a duplicate. Normally, an id
column would be an identity column that is automatically incremented for each value. This would prevent duplicates. You would define it as:
create table test_table (
id int not null identity(1, 1),
. . .
Then, you would insert into it using:
insert into test_table(name)
values (@Name);
The id
would be assigned automatically.
If you want no duplicates just for name
, then create a unique index or unique constraint (really the same thing). You can do this in the table definition just by adding unique
to the column:
create table test_table (
id int not null identity(1, 1),
name varchar(255) unique
. . .
Or by creating a unique index after you have created the table:
create index test_table_name on test_table(name)
(Or by explicitly creating a constraint, which is another method.)