Re: [QUESTIONS] varchar vs text
От | Thomas G. Lockhart |
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Тема | Re: [QUESTIONS] varchar vs text |
Дата | |
Msg-id | 34F9D317.DB96E2A7@alumni.caltech.edu обсуждение исходный текст |
Ответы |
Re: [QUESTIONS] varchar vs text
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Список | pgsql-hackers |
> > > Varchar currently (in 6.2.1 and below) takes up the entire length specified > > > in the definition, despite the fact the value in it may actually be > > > shorter. Text takes only the space taken by the value. > > > > Thanks for the clarification. In this case, what happens with varchar's > > length if the original definition for that field leaves length undefined? > > Does it behave like text in that case? > > You really shouldn't be doing that. Not sure what happens. Not a good > idea: > > create table test (x varchar); ?? This was defined to be a varchar of unlimited length, much like, or identical to, text. Should this now be disallowed? If so, we can fix the parser to disallow it so people don't get misled. > > I also vaguely recall seeing a message last year about the use of indexes > > in queries: that in [some circumstances] indexes built on varchar fields > > don't get used and a sequential scan through all records takes place > > instead. Is there any distinction between varchar and text here? > > Don't remember that. This was probably Bruce's improvements to allow indices on some pattern matching. Doesn't make a distinction between these types in its behavior. - Tom
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