Re: beginner Table data type question
От | davidb@vectormath.com |
---|---|
Тема | Re: beginner Table data type question |
Дата | |
Msg-id | 002401bfc1b9$471719b0$0602010a@bullwinkle.vectormath обсуждение исходный текст |
Ответ на | beginner Table data type question (Richard Smith <ozric@tampabay.rr.com>) |
Список | pgsql-general |
Richard, For constraints see: http://www.postgresql.org/doxlist.html then select Documentation then select Integrated Document then select Alter Table For Column definitions: I believe some other implementations of SQL allow you to alter columns as long as you are keeping the same basic datatype and increasing the size, but require a copy-drop-add-copy if you are changing the basic datatype or decreasing the size. Postgres requires a copy-drop-add-copy for any change to column definitions. David Boerwinkle -----Original Message----- From: Richard Smith <ozric@tampabay.rr.com> To: pgsql-general@postgresql.org.pgsql-questions@postgreSQL.org <pgsql-general@postgresql.org.pgsql-questions@postgreSQL.org> Date: Friday, May 19, 2000 11:12 AM Subject: [GENERAL] beginner Table data type question >Hi, I just start using pgsql and I am new to SQL also. I have read lots >of >documents on this and I cant seem to find the answer, perhaps you can >help me. > >Say I have a table: > >pgsql=> \d test_table > >test_table >------------------------------ >f1| CHAR (40) >f2| CHAR (40) > >Somewhere down the line I need to change the data type on f2 to CHAR >(50) and add constrains like UNIQUE. What is the best was to change >tables in this way? >Can I just make a new table the way I want and COPY the data out of the >old table and COPY it back in? do I use CAST ? Is there some ALTER >TABLE tablename MODIFY command I can use? > >This question has been bugging me for awhile. Because I am new to SQL I >find that I make bad design choices about data types and such all the >time. So I need to know the best way to change them. > >Richard
В списке pgsql-general по дате отправления: