SQL CREATE ALTER DROP TABLE: Difference between revisions

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==Add/Remove a Constraint==
==Add/Remove a Constraint==
<syntaxhighlight lang='sql'>
===<tt>NOT NULL</tt>===
ALTER TABLE person ADD COLUMN birthday DATE;
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</syntaxhighlight>
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<syntaxhighlight lang='sql'>
| [[PostgreSQL_DDL_Operations#NOT_NULL|PostgreSQL]] || [[MySQL_DDL_Operations|MySQL]]
ALTER TABLE person DROP COLUMN birthday;
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===<tt>PRIMARY KEY</tt>===
</syntaxhighlight>
</syntaxhighlight>
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:{| class="wikitable" style="text-align: left;"
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| [[PostgreSQL_DDL_Operations#Add/Remove_a_Constraint|PostgreSQL]] || [[MySQL_DDL_Operations|MySQL]]
| [[PostgreSQL_DDL_Operations#PRIMARY_KEY|PostgreSQL]] || [[MySQL_DDL_Operations|MySQL]]
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Revision as of 19:24, 23 May 2024

Internal

Overview

CREATE

CREATE [TEMPORARY] TABLE person 
( id smallint, 
  name varchar(30) NOT NULL, 
  CONSTRAINT pk_person PRIMARY KEY (id)
);
PostgreSQL MySQL

If the TEMPORARY keyword is used, the created table will be temporary instead of permanent.

ALTER

ALTER TABLE person [...]

Add/Remove a Column

ALTER TABLE person ADD COLUMN birthday DATE;
ALTER TABLE person DROP COLUMN birthday;
PostgreSQL MySQL

Add/Remove a Constraint

NOT NULL

PostgreSQL MySQL

PRIMARY KEY

</syntaxhighlight>

PostgreSQL MySQL

DROP

DROP TABLE person [...]
PostgreSQL MySQL

Features

AUTO_INCREMENT

AUTO_INCREMENT