SQL: 03 - KEY and INDEX

PRIMARY KEY

Syntax

PRIMARY KEY (ID

 

Example

CONSTRAINT newIDCol PRIMARY KEY (ID,MediaColor)

 

FOREIGN KEY

Points to a PRIMARY KEY in another table

Syntax

 

Example

FOREIGN KEY (ID) REFERENCES projectlist(ID)

 

DROP

Syntax

 

Example

ALTER TABLE medialist

DROP FOREIGN KEY ID

 

MySQL

CREATE TABLE medialistarchive LIKE medialist;

INSERT INTO medialistarchive LIKE medialist;

 

CREATE INDEX

Syntax

CREATE INDEX index_name

ON table_name (column_name )

 

CREATE UNIQUE INDEX index_name

ON table_name (column_name)

 

Example

CREATE UNIQUE INDEX medialist_Index

ON MediaIndex (MediaColor)