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Remove FAQ mention of DROP column.

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Bruce Momjian 2005-02-01 01:41:37 +00:00
parent 25deba3141
commit 2ccf79a6a1
2 changed files with 12 additions and 35 deletions
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21
doc/FAQ
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@ -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.

26
doc/src/FAQ/FAQ.html
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@ -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>.