diff options
author | Bruce Momjian | 2005-02-01 01:41:37 +0000 |
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committer | Bruce Momjian | 2005-02-01 01:41:37 +0000 |
commit | 2ccf79a6a16728911602d48c7bfc661e759d20e3 (patch) | |
tree | 6224d0a8141c5e6974b1eb1f7eb9c0efd2e6b4f4 /doc/FAQ | |
parent | 25deba3141ecc2d29422e7cd06d0efe0a1d94be1 (diff) |
Remove FAQ mention of DROP column.
Diffstat (limited to 'doc/FAQ')
-rw-r--r-- | doc/FAQ | 21 |
1 files changed, 6 insertions, 15 deletions
@@ -1,7 +1,7 @@ Frequently Asked Questions (FAQ) for PostgreSQL - Last updated: Mon Jan 31 20:35:58 EST 2005 + Last updated: Mon Jan 31 20:41:21 EST 2005 Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us) @@ -51,7 +51,7 @@ 4.1) How do I SELECT only the first few rows of a query? A random row? 4.2) How do I find out what tables, indexes, databases, and users are defined? How do I see the queries used by psql to display them? - 4.3) How do you remove a column from a table, or change its data type? + 4.3) How do you change a column's data type? 4.4) What is the maximum size for a row, a table, and a database? 4.5) How much database disk space is required to store data from a typical text file? @@ -491,25 +491,16 @@ query to get information about the database. There are also system tables beginning with pg_ that describe these - too. Use psql -l will list all databases. + too. + + Use psql -l will list all databases. Also try the file pgsql/src/tutorial/syscat.source. It illustrates many of the SELECTs needed to get information from the database system tables. - 4.3) How do you remove a column from a table, or change its data type? + 4.3) How do you change a column's data type? - DROP COLUMN functionality was added in release 7.3 with ALTER TABLE - DROP COLUMN. In earlier versions, you can do this: - BEGIN; - LOCK TABLE old_table; - SELECT ... -- select all columns but the one you want to remove - INTO TABLE new_table - FROM old_table; - DROP TABLE old_table; - ALTER TABLE new_table RENAME TO old_table; - COMMIT; - Changing the data type of a column can be done easily in 8.0 and later with ALTER TABLE ALTER COLUMN TYPE. |