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PostgreSQL - Create table with FOREIGN KEY
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In this article, we would like to show you how to create a table with FOREIGN KEY in PostgreSQL.
Quick solution:
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CREATE TABLE "table1_name" (2
"column1" DATA_TYPE,3
"column2" DATA_TYPE,4
"columnN" DATA_TYPE,5
PRIMARY KEY ("column_name"),6
FOREIGN KEY ("column_name") REFERENCES "table2_name"("reference_column")7
);Note:
Go to the official documentation to see available
DATA_TYPES.
In this example, we will create two tables:
groupstable with two columns:id- withPRIMARY KEYconstraintgroup_name
and users table with three columns:
id- withPRIMARY KEYconstraintusernamegroup_id- which will be ourFOREIGN KEYwithgroups.idcolumn reference
Query:
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CREATE TABLE "groups" (2
"id" SERIAL,3
"group_name" VARCHAR(50) NOT NULL,4
PRIMARY KEY ("id")5
);6
7
CREATE TABLE "users" (8
"id" SERIAL,9
"username" VARCHAR(50) NOT NULL,10
"group_id" INTEGER,11
PRIMARY KEY ("id"),12
FOREIGN KEY ("group_id") REFERENCES "groups"("id")13
);Result:
As we see in the second picture, the group_id column from users table has FOREIGN KEY constraint which refers to the id column from groups table with PRIMARY KEY constraint.
