Using SQL Constraints

Set c1 and c2 as a primary key

CREATE TABLE t(
c1 INT, c2 INT, c3 VARCHAR,
PRIMARY KEY (c1,c2)
);

Set c2 column as a foreign key

CREATE TABLE t1(
c1 INT PRIMARY KEY,
c2 INT,
FOREIGN KEY (c2) REFERENCES t2(c2)
);

Make the values in c1 and c2 unique

CREATE TABLE t(
c1 INT, c1 INT,
UNIQUE(c2,c3)
);

Ensure c1 > 0 and values in c1 >= c2

CREATE TABLE t(
c1 INT, c2 INT,
CHECK(c1> 0 AND c1 >= c2)
);

Set values in c2 column not NULL

CREATE TABLE t(
c1 INT PRIMARY KEY,
c2 VARCHAR NOT NULL
);

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