MySQL Constraints

Primary Key

Implementation:

CREATE TABLE sample (
   <pk-col> <type> <attr> PRIMARY KEY <attr>
);

CREATE TABLE sample (
   <pk-col> <type> <attr>,
   PRIMARY KEY (<pk-col>)
);

CREATE TABLE sample (
   <pk-col> <type> <attr>,
   CONSTRAINT <pk-name> PRIMARY KEY (<pk-col>)
);

Foreign Key

Implementation:

CREATE TABLE sample (
   <fk-col> <type> <attr>,
   FOREIGN KEY (<fk-col>) REFERENCES <ref-table> (<ref-pk-col>)
);

CREATE TABLE sample (
   <fk-col> <type> <attr>,
   CONSTRAINT <fk-name> FOREIGN KEY (<fk-col>) REFERENCES <ref-table> (<ref-pk-col>)
);

Not Null

Implementation:

CREATE TABLE sample (
   <col> <type> <attr> NOT NULL <attr>
);

Unique

Implementation:

CREATE TABLE sample (
   <col> <type> <attr> UNIQUE <attr>
);

CREATE TABLE sample (
   <col> <type> <attr>
   UNIQUE (col)
);

CREATE TABLE sample (
   <col> <type> <attr>
   CONSTRAINT <uq-name> UNIQUE (col)
);

Check

Implementation:

CREATE TABLE sample (
   <col> <type> <attr>
   CHECK (<condition>)
);

CREATE TABLE sample (
   <col> <type> <attr>
   CONSTRAINT <chk-name> CHECK (<condition>)
);

Default

Implementation:

CREATE TABLE sample (
   <col> <type> <attr> DEFAULT <def-val>
);

CREATE TABLE sample (
   <col> <type> <attr> DEFAULT <func>
);

Indices

Platzhalter