SQL Constraint names

Question

If we have query for creating table like this..

create table if not exists food
(
     id int not null auto_increment,
     user_id int,
     name varchar(30),

     constraint pk_food primary key(id,name),
     foreign key(user_id) references userss(id)
);

What does pk_food mean in this example? I know this is a constraint name, but for what we should be give a name for constraint, if its working without?

create table if not exists food
(
     id int not null auto_increment,
     user_id int,
     name varchar(30),

     primary key (id, name),
     foreign key (user_id) references userss(id)
);

I mean.. how to use these names and for what we need it?

Related [Named CONSTRAINT benefits](https://stackoverflow.com/questions/5897913/named-constraint-benefits) — Lukasz Szozda, Mar 21 '20 at 21:50

Gordon Linoff · Accepted Answer · 2020-03-14T19:56:13.870

5

You gives constraints names for basically two reasons:

You can better understand the error message when the constraint is violated.
You can more easily find the constraint if you want to delete it.

edited Mar 14 '20 at 19:56

answered Mar 14 '20 at 17:28

Gordon Linoff

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thank you! because i not found any information in doc – Wembley Mar 14 '20 at 17:34

SQL Constraint names

1 Answers1