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sqlconstraintsprimary-keycreate-table

what's the difference between those two sql statements?

what's the difference between those two sql statements to set primary key constraints?

first one:

CREATE TABLE Persons (
    ID int NOT NULL,
    PRIMARY KEY (ID)
);

second one:

CREATE TABLE Persons (

ID INT NOT NULL ,
constraint pk_Persons primary key (ID)
)

thanks in advance

Solution

  • In the second version, you can give a name to your constraint and you can make primary key with multiple columns, allowing you to drop it using the name instead of having to name every column of a composite constraint.

    This is a duplicate question from What is the difference between Primary Key only and Primary Key constraint?