Re: A general database question!
От | Jeff Davis |
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Тема | Re: A general database question! |
Дата | |
Msg-id | 200203212329.PAA17841@mail.ucsd.edu обсуждение исходный текст |
Ответ на | A general database question! (Dmitry Tkach <dmitry@openratings.com>) |
Список | pgsql-general |
> I have a general database design question for you... > Suppose, I have a database of entities, that have two attributes, say, > location and name. Location is numerical and name is a varchar. > I need to be able to search by both location and name (e.g. get all the > entries whose location is 1 and name is John etc...). > It is simple so far - I'd just create an an index on both location and > name... > I am not quite understanding why a multi-column index won't work. Can you explain a little more? Here is what I was thinking: create table entity( type int, location int, name varchar(100) not null, ); create unique index my_index on entity(location,name); It seems as though an "and" query would run quickly. It also seems as though if you needed to get a few records that were one of several names, a query such as the following would run quickly: select * from entity where location = 5 and (name = 'joe' or name='joseph'); or are the aliases a seperate attribute? I am not clear on exactly where the alias comes in. Regards, Jeff
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