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POMYSQL, When defining a table does the UNIQUE constraint have to be used in conjunction with an INTEGER or can it be any datatype?
 

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  1. POMYSQL, When defining a table does the UNIQUE constraint have to be used in conjunction with an INTEGER or can it be any datatype?
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    <p>I am wanting to have a label column (<code>VARCHAR</code>) and I want it to be unique, but when I try to create the table it seems to be throwing an error. Can a unique constraint only be used in conjunction with an INTEGER or will it work with other datatypes as well. The error I am getting is (<code>ERRNO 150</code>)</p> <pre><code>CREATE TABLE IF NOT EXISTS `user`( user_id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, username VARCHAR(50) NOT NULL, `password` VARCHAR(255) NOT NULL ); CREATE TABLE IF NOT EXISTS `element`( element_id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, label VARCHAR(5) NOT NULL DEFAULT '', parent_id INT NULL, user_id INT NOT NULL, created_on TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP, edited_on TIMESTAMP NOT NULL, UNIQUE(label), KEY element_1 (label), CONSTRAINT FK_element_1 FOREIGN KEY (user_id) REFERENCES `user` (user_id), CONSTRAINT FK_element_2 FOREIGN KEY (parent_id) REFERENCES `element` (element_id) ); </code></pre>
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    1. PO
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      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USBrook Julias
    1. USBrook Julias
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
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      1. PTAnswer
    1. VO
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      1. POMYSQL, When defining a table does the UNIQUE constraint have to be used in conjunction with an INTEGER or can it be any datatype?
      1. This table or related slice is empty.
      1. VTUpMod
    1. CO@OMG: Except `TEXT` and `BLOB`, right?
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      1. POMYSQL, When defining a table does the UNIQUE constraint have to be used in conjunction with an INTEGER or can it be any datatype?
      1. USypercubeᵀᴹ
    2. COI have posted the SQL querey. This is only the second table to be created if needed I could give you the SQL for the one prior.
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      1. POMYSQL, When defining a table does the UNIQUE constraint have to be used in conjunction with an INTEGER or can it be any datatype?
      1. USBrook Julias
    3. CO@ypercube: Dunno why `TEXT` wouldn't be supported - there's no mention of any data type requirements for unique constraints in MySQL [here](http://dev.mysql.com/doc/refman/5.0/en/create-table.html) or [here](http://dev.mysql.com/doc/refman/5.0/en/constraint-primary-key.html)
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      1. POMYSQL, When defining a table does the UNIQUE constraint have to be used in conjunction with an INTEGER or can it be any datatype?
      1. USOMG Ponies
 

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