diff --git a/doc/FAQ b/doc/FAQ index c092e10b9cfca55ebb42b2f1da79a973d2a954d0..3c35b3c2ec6adb04ed7fb84d493bbed7d368f197 100644 --- a/doc/FAQ +++ b/doc/FAQ @@ -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. diff --git a/doc/src/FAQ/FAQ.html b/doc/src/FAQ/FAQ.html index 1385d5901271cf75e3527ca556a2e554b2605626..71fd85771075d7f2e82deb2911ba675625ba8c43 100644 --- a/doc/src/FAQ/FAQ.html +++ b/doc/src/FAQ/FAQ.html @@ -10,7 +10,7 @@ alink="#0000ff"> <H1>Frequently Asked Questions (FAQ) for PostgreSQL</H1> - <P>Last updated: Mon Jan 31 20:35:58 EST 2005</P> + <P>Last updated: Mon Jan 31 20:41:21 EST 2005</P> <P>Current maintainer: Bruce Momjian (<A href= "mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>) @@ -74,8 +74,7 @@ <A href="#4.2">4.2</A>) How do I find out what tables, indexes, databases, and users are defined? How do I see the queries used by <I>psql</I> to display them?<BR> - <A href="#4.3">4.3</A>) How do you remove a column from a - table, or change its data type?<BR> + <A href="#4.3">4.3</A>) How do you change a column's data type?<BR> <A href="#4.4">4.4</A>) What is the maximum size for a row, a table, and a database?<BR> <A href="#4.5">4.5</A>) How much database disk space is required @@ -645,28 +644,15 @@ database.</P> <P>There are also system tables beginning with <I>pg_</I> that describe - these too. Use <I>psql -l</I> will list all databases.</P> + these too.</P> + + <P>Use <I>psql -l</I> will list all databases.</P> <P>Also try the file <I>pgsql/src/tutorial/syscat.source</I>. It illustrates many of the <SMALL>SELECT</SMALL>s needed to get information from the database system tables.</P> - <H4><A name="4.3">4.3</A>) How do you remove a column from a - table, or change its data type?</H4> - - <P><SMALL>DROP COLUMN</SMALL> functionality was added in release 7.3 - with <SMALL>ALTER TABLE DROP COLUMN</SMALL>. In earlier versions, - you can do this:</P> -<PRE> - 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; -</PRE> + <H4><A name="4.3">4.3</A>) How do you change a column's data type?</H4> <P>Changing the data type of a column can be done easily in 8.0 and later with <SMALL>ALTER TABLE ALTER COLUMN TYPE</SMALL>.