Movatterモバイル変換

[0]ホーム
URL:

Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

 Sign up
Appearance settings

Commitc805491

Browse files
committed
Update FAQ.
1 parent728b0aa commitc805491

File tree

2 files changed

+31
-46
lines changed

2 files changed

+31
-46
lines changed

‎doc/FAQ‎

Lines changed: 16 additions & 23 deletions
Original file line numberDiff line numberDiff line change
@@ -67,14 +67,14 @@
6767
4.6) What is the maximum size for a row, table, database?
6868
4.7) How much database disk space is required to store data from a
6969
typical text file?
70-
4.8) How do I find out whatindices oroperations are defined in the
70+
4.8) How do I find out whattables orindexes are defined in the
7171
database?
7272
4.9) My queries are slow or don't make use of the indexes. Why?
7373
4.10) How do I see how the query optimizer is evaluating my query?
7474
4.11) What is an R-tree index?
75-
4.12) What is Genetic QueryOptimization?
76-
4.13) How do Ido regular expression searches and case-insensitive
77-
regular expression searches?
75+
4.12) What istheGenetic QueryOptimizer?
76+
4.13) How do Iperform regular expression searches and
77+
case-insensitiveregular expression searches?
7878
4.14) In a query, how do I detect if a field is NULL?
7979
4.15) What is the difference between the various character types?
8080
4.16.1) How do I create a serial/auto-incrementing field?
@@ -90,7 +90,7 @@
9090
Why?
9191
4.22) How do I create a column that will default to the current time?
9292
4.23) Why are my subqueries using IN so slow?
93-
4.24) How do Ido an outer join?
93+
4.24) How do Iperform an outer join?
9494

9595
Extending PostgreSQL
9696

@@ -677,8 +677,7 @@ Maximum number of indexes on a table? unlimited
677677
Indexes do not require as much overhead, but do contain the data that
678678
is being indexed, so they can be large also.
679679

680-
4.8) How do I find out what indices or operations are defined in the
681-
database?
680+
4.8) How do I find out what tables or indexes are defined in the database?
682681

683682
psql has a variety of backslash commands to show such information. Use
684683
\? to see them.
@@ -739,21 +738,19 @@ Maximum number of indexes on a table? unlimited
739738
extending R-trees requires a bit of work and we don't currently have
740739
any documentation on how to do it.
741740

742-
4.12) What is Genetic QueryOptimization?
741+
4.12) What istheGenetic QueryOptimizer?
743742

744743
The GEQO module speeds query optimization when joining many tables by
745744
means of a Genetic Algorithm (GA). It allows the handling of large
746745
join queries through nonexhaustive search.
747746

748-
4.13) How do Ido regular expression searches and case-insensitive regular
749-
expression searches?
747+
4.13) How do Iperform regular expression searches and case-insensitive
748+
regularexpression searches?
750749

751750
The ~ operator does regular expression matching, and ~* does
752-
case-insensitive regular expression matching. There is no
753-
case-insensitive variant of the LIKE operator, but you can get the
754-
effect of case-insensitive LIKE with this:
755-
WHERE lower(textfield) LIKE lower(pattern)
756-
751+
case-insensitive regular expression matching. The case-insensitive
752+
variant of LIKE is called ILIKE.
753+
757754
4.14) In a query, how do I detect if a field is NULL?
758755

759756
You test the column with IS NULLIS NOT NULL.
@@ -893,13 +890,9 @@ BYTEA bytea variable-length byte array (null-safe)
893890
Depending on your shell, only one of these may succeed, but it will
894891
set your process data segment limit much higher and perhaps allow the
895892
query to complete. This command applies to the current process, and
896-
all subprocessesHTML & CSS specifications are available from
897-
http://www.w3.org/ To learn more about Tidy see
898-
http://www.w3.org/People/Raggett/tidy/ Please send bug reports to Dave
899-
Raggett care of Lobby your company to join W3C, see
900-
http://www.w3.org/Consortium created after the command is run. If you
901-
are having a problem with the SQL client because the backend is
902-
returning too much data, try it before starting the client.
893+
all subprocesses created after the command is run. If you are having a
894+
problem with the SQL client because the backend is returning too much
895+
data, try it before starting the client.
903896

904897
4.20) How do I tell what PostgreSQL version I am running?
905898

@@ -940,7 +933,7 @@ SELECT *
940933

941934
We hope to fix this limitation in a future release.
942935

943-
4.24) How do Ido an outer join?
936+
4.24) How do Iperform an outer join?
944937

945938
PostgreSQL 7.1 and later supports outer joins using the SQL standard
946939
syntax. Here are two examples:

‎doc/src/FAQ/FAQ.html‎

Lines changed: 15 additions & 23 deletions
Original file line numberDiff line numberDiff line change
@@ -103,15 +103,15 @@ <H2>Operational Questions</H2>
103103
database?<BR>
104104
<Ahref="#4.7">4.7</A>) How much database disk space is required
105105
to store data from a typical text file?<BR>
106-
<Ahref="#4.8">4.8</A>) How do I find out whatindices or
107-
operations are defined in the database?<BR>
106+
<Ahref="#4.8">4.8</A>) How do I find out whattables or
107+
indexes are defined in the database?<BR>
108108
<Ahref="#4.9">4.9</A>) My queries are slow or don't make use of
109109
the indexes. Why?<BR>
110110
<Ahref="#4.10">4.10</A>) How do I see how the query optimizer is
111111
evaluating my query?<BR>
112112
<Ahref="#4.11">4.11</A>) What is an R-tree index?<BR>
113-
<Ahref="#4.12">4.12</A>) What is Genetic QueryOptimization?<BR>
114-
<Ahref="#4.13">4.13</A>) How do Ido regular expression searches
113+
<Ahref="#4.12">4.12</A>) What istheGenetic QueryOptimizer?<BR>
114+
<Ahref="#4.13">4.13</A>) How do Iperform regular expression searches
115115
and case-insensitive regular expression searches?<BR>
116116
<Ahref="#4.14">4.14</A>) In a query, how do I detect if a field
117117
is<SMALL>NULL</SMALL>?<BR>
@@ -137,7 +137,7 @@ <H2>Operational Questions</H2>
137137
default to the current time?<BR>
138138
<Ahref="#4.23">4.23</A>) Why are my subqueries using
139139
<CODE><SMALL>IN</SMALL></CODE> so slow?<BR>
140-
<Ahref="#4.24">4.24</A>) How do Ido an<I>outer</I> join?<BR>
140+
<Ahref="#4.24">4.24</A>) How do Iperform an<I>outer</I> join?<BR>
141141

142142

143143
<CENTER>
@@ -873,8 +873,8 @@ <H4><A name="4.7">4.7</A>) How much database disk space is required
873873
<P>Indexes do not require as much overhead, but do contain the data
874874
that is being indexed, so they can be large also.</P>
875875

876-
<H4><Aname="4.8">4.8</A>) How do I find out whatindices or
877-
operations are defined in the database?</H4>
876+
<H4><Aname="4.8">4.8</A>) How do I find out whattables or
877+
indexes are defined in the database?</H4>
878878

879879
<P><I>psql</I> has a variety of backslash commands to show such
880880
information. Use \? to see them.</P>
@@ -943,25 +943,21 @@ <H4><A name="4.11">4.11</A>) What is an R-tree index?</H4>
943943
practice, extending R-trees requires a bit of work and we don't
944944
currently have any documentation on how to do it.</P>
945945

946-
<H4><Aname="4.12">4.12</A>) What is Genetic Query
947-
Optimization?</H4>
946+
<H4><Aname="4.12">4.12</A>) What istheGenetic Query
947+
Optimizer?</H4>
948948

949949
<P>The<SMALL>GEQO</SMALL> module speeds query optimization when
950950
joining many tables by means of a Genetic Algorithm (GA). It allows
951951
the handling of large join queries through nonexhaustive
952952
search.</P>
953953

954-
<H4><Aname="4.13">4.13</A>) How do Ido regular expression
954+
<H4><Aname="4.13">4.13</A>) How do Iperform regular expression
955955
searches and case-insensitive regular expression searches?</H4>
956956

957957
<P>The<I>~</I> operator does regular expression matching, and
958-
<I>~*</I> does case-insensitive regular expression matching. There
959-
is no case-insensitive variant of the<SMALL>LIKE</SMALL> operator,
960-
but you can get the effect of case-insensitive<SMALL>LIKE</SMALL>
961-
with this:</P>
962-
<PRE>
963-
WHERE lower(textfield) LIKE lower(pattern)
964-
</PRE>
958+
<I>~*</I> does case-insensitive regular expression matching. The
959+
case-insensitive variant of<SMALL>LIKE</SMALL>
960+
is called<SMALL>ILIKE</SMALL>.</P>
965961

966962
<H4><Aname="4.14">4.14</A>) In a query, how do I detect if a field
967963
is<SMALL>NULL</SMALL>?</H4>
@@ -1147,11 +1143,7 @@ <H4><A name="4.19">4.19</A>) Why do I get the error <I>"FATAL:
11471143
Depending on your shell, only one of these may succeed, but it will
11481144
set your process data segment limit much higher and perhaps allow
11491145
the query to complete. This command applies to the current process,
1150-
and all subprocessesHTML & CSS specifications are available from http://www.w3.org/
1151-
To learn more about Tidy see http://www.w3.org/People/Raggett/tidy/
1152-
Please send bug reports to Dave Raggett care of<html-tidy@w3.org>
1153-
Lobby your company to join W3C, see http://www.w3.org/Consortium
1154-
created after the command is run. If you are
1146+
and all subprocesses created after the command is run. If you are
11551147
having a problem with the<SMALL>SQL</SMALL> client because the
11561148
backend is returning too much data, try it before starting the
11571149
client.
@@ -1212,7 +1204,7 @@ <H4><A name="4.23">4.23</A>) Why are my subqueries using
12121204
</PRE>
12131205
We hope to fix this limitation in a future release.
12141206

1215-
<H4><Aname="4.24">4.24</A>) How do Ido an<I>outer</I> join?<BR>
1207+
<H4><Aname="4.24">4.24</A>) How do Iperform an<I>outer</I> join?<BR>
12161208
</H4>
12171209

12181210
<P>PostgreSQL 7.1 and later supports outer joins using the SQL

0 commit comments

Comments
 (0)
[8]ページ先頭
©2009-2025 Movatter.jp