On 11/22/05, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: > I am in the process re-implementing some pgsql table declarations into a > MySQL database. I have this one line where I say > ... > fieldname TEXT UNIQUE, > ... > in my pgsql table because I want to ensure that no one enters the same thing > in this field and I didn't choose VARCHAR type because I have no idea how > possibly long I might need to let the field be... > > ... but MySQL doesn't like this because a TEXT datatype is considered a BLOB > that can't be indexed and it can't guarantee will be UNIQUE apparently... > > So I can't help but wonder, can Postgres really guarantee a TEXT field to be > UNIQUE... or is declaring a TEXT field UNIQUE something an uninformed, novice > user would do?... or is it something indicative of the strength and/or > weeknesses that separate the functionality of the two DBMSs. > > Ferindo Middleton >
TEXT fileds can be indexed in postgres and AFAIK it can be indexed with a unique index (and i don't see any good reason to think it can't guarantee uniqueness)... but you have a limitation, btree index rows can only have certain size (i don't remember the numbers now)... so if you exceed that size (and in a text field you can) you will get an error... you have to control within your application that... -- Atentamente, Jaime Casanova (DBA: DataBase Aniquilator ;) ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
