[PATCH] hstore documentation update
in [PgSql]
|
From: Bruce Momjian on 30 Nov 2009 12:56 Applied. Thanks. --------------------------------------------------------------------------- David E. Wheeler wrote: > From: David E. Wheeler <david(a)justatheory.com> > > As I threatened when I reviewed hstore in the last two commit > fests, I've finally seen may way to edit the documentation. This > is mostly word-smithing, making sure that all `>`s are encoded, > making sure that various text is properly tagged with `<type>` > and `<literal>` tags, plus an extra note or two. I submit this > patch for the next CommitFest (though I don't know how much CFing > is needed for a pure documenation patch). > > Best, > > David > > --- > doc/src/sgml/hstore.sgml | 190 +++++++++++++++++++++++++--------------------- > 1 files changed, 102 insertions(+), 88 deletions(-) > > diff --git a/doc/src/sgml/hstore.sgml b/doc/src/sgml/hstore.sgml > index f237be7..fcff6e3 100644 > *** a/doc/src/sgml/hstore.sgml > --- b/doc/src/sgml/hstore.sgml > *************** > *** 8,69 **** > </indexterm> > > <para> > ! This module implements a data type <type>hstore</> for storing sets of > ! (key,value) pairs within a single <productname>PostgreSQL</> data field. > This can be useful in various scenarios, such as rows with many attributes > that are rarely examined, or semi-structured data. Keys and values are > ! arbitrary text strings. > </para> > > <sect2> > <title><type>hstore</> External Representation</title> > > <para> > ! The text representation of an <type>hstore</> value includes zero > ! or more <replaceable>key</> <literal>=></> <replaceable>value</> > ! items, separated by commas. For example: > > <programlisting> > ! k => v > ! foo => bar, baz => whatever > ! "1-a" => "anything at all" > </programlisting> > > ! The order of the items is not considered significant (and may not be > ! reproduced on output). Whitespace between items or around the > ! <literal>=></> sign is ignored. Use double quotes if a key or > ! value includes whitespace, comma, <literal>=</> or <literal>></>. > ! To include a double quote or a backslash in a key or value, precede > ! it with another backslash. > </para> > > <para> > ! A value (but not a key) can be a SQL NULL. This is represented as > > <programlisting> > ! key => NULL > </programlisting> > > ! The <literal>NULL</> keyword is not case-sensitive. Again, use > ! double quotes if you want the string <literal>null</> to be treated > ! as an ordinary data value. > </para> > > <note> > <para> > ! Keep in mind that the above format, when used to input hstore values, > ! applies <emphasis>before</> any required quoting or escaping. If you > ! are passing an hstore literal via a parameter, then no additional > ! processing is needed. If you are passing it as a quoted literal > ! constant, then any single-quote characters and (depending on the > ! setting of <varname>standard_conforming_strings</>) backslash characters > ! need to be escaped correctly. See <xref linkend="sql-syntax-strings">. > </para> > </note> > > <para> > ! Double quotes are always used to surround key and value > ! strings on output, even when this is not strictly necessary. > </para> > > </sect2> > --- 8,83 ---- > </indexterm> > > <para> > ! This module implements the <type>hstore</> data type for storing sets of > ! key/value pairs within a single <productname>PostgreSQL</> value. > This can be useful in various scenarios, such as rows with many attributes > that are rarely examined, or semi-structured data. Keys and values are > ! simply text strings. > </para> > > <sect2> > <title><type>hstore</> External Representation</title> > > <para> > ! > ! The text representation of an <type>hstore</>, used for input and output, > ! includes zero or more <replaceable>key</> <literal>=></> > ! <replaceable>value</> pairs separated by commas. Some examples: > > <programlisting> > ! k => v > ! foo => bar, baz => whatever > ! "1-a" => "anything at all" > </programlisting> > > ! The order of the pairs is not significant (and may not be reproduced on > ! output). Whitespace between pairs or around the <literal>=></> sign is > ! ignored. Double-quote keys and values that include whitespace, commas, > ! <literal>=</>s or <literal>></>s. To include a double quote or a > ! backslash in a key or value, escape it with a backslash. > </para> > > <para> > ! Each key in an <type>hstore</> is unique. If you declare an <type>hstore</> > ! with duplicate keys, only one will be stored in the <type>hstore</> and > ! there is no guarantee as to which will be kept: > > <programlisting> > ! % select 'a=>1,a=>2'::hstore; > ! hstore > ! ---------- > ! "a"=>"1" > </programlisting> > + </para> > > ! <para> > ! A value (but not a key) can be an SQL <literal>NULL</>. For example: > ! > ! <programlisting> > ! key => NULL > ! </programlisting> > ! > ! The <literal>NULL</> keyword is case-insensitive. Double-quote the > ! <literal>NULL</> to treat it as the ordinary string "NULL". > </para> > > <note> > <para> > ! Keep in mind that the <type>hstore</> text format, when used for input, > ! applies <emphasis>before</> any required quoting or escaping. If you are > ! passing an <type>hstore</> literal via a parameter, then no additional > ! processing is needed. But if you're passing it as a quoted literal > ! constant, then any single-quote characters and (depending on the setting of > ! the <varname>standard_conforming_strings</> configuration parameter) > ! backslash characters need to be escaped correctly. See > ! <xref linkend="sql-syntax-strings"> for more on the handling of string > ! constants. > </para> > </note> > > <para> > ! On output, double quotes always surround keys and values, even when it's > ! not strictly necessary. > </para> > > </sect2> > *************** > *** 87,128 **** > <tbody> > <row> > <entry><type>hstore</> <literal>-></> <type>text</></entry> > ! <entry>get value for key (null if not present)</entry> > <entry><literal>'a=>x, b=>y'::hstore -> 'a'</literal></entry> > <entry><literal>x</literal></entry> > </row> > > <row> > <entry><type>hstore</> <literal>-></> <type>text[]</></entry> > ! <entry>get values for keys (null if not present)</entry> > <entry><literal>'a=>x, b=>y, c=>z'::hstore -> ARRAY['c','a']</literal></entry> > <entry><literal>{"z","x"}</literal></entry> > </row> > > <row> > <entry><type>text</> <literal>=></> <type>text</></entry> > ! <entry>make single-item <type>hstore</></entry> > <entry><literal>'a' => 'b'</literal></entry> > <entry><literal>"a"=>"b"</literal></entry> > </row> > > <row> > <entry><type>text[]</> <literal>=></> <type>text[]</></entry> > ! <entry>construct an <type>hstore</> value from separate key and value arrays</entry> > <entry><literal>ARRAY['a','b'] => ARRAY['1','2']</literal></entry> > <entry><literal>"a"=>"1","b"=>"2"</literal></entry> > </row> > > <row> > <entry><type>hstore</> <literal>=></> <type>text[]</></entry> > ! <entry>extract a subset of an <type>hstore</> value</entry> > <entry><literal>'a=>1,b=>2,c=>3'::hstore => ARRAY['b','c','x']</literal></entry> > <entry><literal>"b"=>"2", "c"=>"3"</literal></entry> > </row> > > <row> > <entry><type>hstore</> <literal>||</> <type>hstore</></entry> > ! <entry>concatenation</entry> > <entry><literal>'a=>b, c=>d'::hstore || 'c=>x, d=>q'::hstore</literal></entry> > <entry><literal>"a"=>"b", "c"=>"x", "d"=>"q"</literal></entry> > </row> > --- 101,142 ---- > <tbody> > <row> > <entry><type>hstore</> <literal>-></> <type>text</></entry> > ! <entry>get value for key (<literal>NULL</> if not present)</entry> > <entry><literal>'a=>x, b=>y'::hstore -> 'a'</literal></entry> > <entry><literal>x</literal></entry> > </row> > > <row> > <entry><type>hstore</> <literal>-></> <type>text[]</></entry> > ! <entry>get values for keys (<literal>NULL</> if not present)</entry> > <entry><literal>'a=>x, b=>y, c=>z'::hstore -> ARRAY['c','a']</literal></entry> > <entry><literal>{"z","x"}</literal></entry> > </row> > > <row> > <entry><type>text</> <literal>=></> <type>text</></entry> > ! <entry>make single-pair <type>hstore</></entry> > <entry><literal>'a' => 'b'</literal></entry> > <entry><literal>"a"=>"b"</literal></entry> > </row> > > <row> > <entry><type>text[]</> <literal>=></> <type>text[]</></entry> > ! <entry>construct an <type>hstore</> from separate key and value arrays</entry> > <entry><literal>ARRAY['a','b'] => ARRAY['1','2']</literal></entry> > <entry><literal>"a"=>"1","b"=>"2"</literal></entry> > </row> > > <row> > <entry><type>hstore</> <literal>=></> <type>text[]</></entry> > ! <entry>extract a subset of an <type>hstore</></entry> > <entry><literal>'a=>1,b=>2,c=>3'::hstore => ARRAY['b','c','x']</literal></entry> > <entry><literal>"b"=>"2", "c"=>"3"</literal></entry> > </row> > > <row> > <entry><type>hstore</> <literal>||</> <type>hstore</></entry> > ! <entry>concatenate <type>hstore</>s</entry> > <entry><literal>'a=>b, c=>d'::hstore || 'c=>x, d=>q'::hstore</literal></entry> > <entry><literal>"a"=>"b", "c"=>"x", "d"=>"q"</literal></entry> > </row> > *************** > *** 178,205 **** > > <row> > <entry><type>hstore</> <literal>-</> <type>hstore</></entry> > ! <entry>delete matching key/value pairs from left operand</entry> > <entry><literal>'a=>1, b=>2, c=>3'::hstore - 'a=>4, b=>2'::hstore</literal></entry> > <entry><literal>"a"=>"1", "c"=>"3"</literal></entry> > </row> > > <row> > <entry><type>record</> <literal>#=</> <type>hstore</></entry> > ! <entry>replace fields in record with matching values from hstore</entry> > <entry>see Examples section</entry> > <entry></entry> > </row> > > <row> > <entry><literal>%%</> <type>hstore</></entry> > ! <entry>convert hstore to array of alternating keys and values</entry> > <entry><literal>%% 'a=>foo, b=>bar'::hstore</literal></entry> > <entry><literal>{a,foo,b,bar}</literal></entry> > </row> > > <row> > <entry><literal>%#</> <type>hstore</></entry> > ! <entry>convert hstore to two-dimensional key/value array</entry> > <entry><literal>%# 'a=>foo, b=>bar'::hstore</literal></entry> > <entry><literal>{{a,foo},{b,bar}}</literal></entry> > </row> > --- 192,219 ---- > > <row> > <entry><type>hstore</> <literal>-</> <type>hstore</></entry> > ! <entry>delete matching pairs from left operand</entry> > <entry><literal>'a=>1, b=>2, c=>3'::hstore - 'a=>4, b=>2'::hstore</literal></entry> > <entry><literal>"a"=>"1", "c"=>"3"</literal></entry> > </row> > > <row> > <entry><type>record</> <literal>#=</> <type>hstore</></entry> > ! <entry>replace fields in <type>record</> with matching values from <type>hstore</></entry> > <entry>see Examples section</entry> > <entry></entry> > </row> > > <row> > <entry><literal>%%</> <type>hstore</></entry> > ! <entry>convert <type>hstore</> to array of alternating keys and values</entry> > <entry><literal>%% 'a=>foo, b=>bar'::hstore</literal></entry> > <entry><literal>{a,foo,b,bar}</literal></entry> > </row> > > <row> > <entry><literal>%#</> <type>hstore</></entry> > ! <entry>convert <type>hstore</> to two-dimensional key/value array</entry> > <entry><literal>%# 'a=>foo, b=>bar'::hstore</literal></entry> > <entry><literal>{{a,foo},{b,bar}}</literal></entry> > </row> > *************** > *** 208,220 **** > </tgroup> > </table> > > <para> > ! (Before PostgreSQL 8.2, the containment operators @> and <@ were > ! respectively called @ and ~. These names are still available, but are > ! deprecated and will eventually be retired. Notice that the old names > ! are reversed from the convention formerly followed by the core geometric > ! datatypes!) > ! </para> > > <table id="hstore-func-table"> > <title><type>hstore</> Functions</title> > --- 222,236 ---- > </tgroup> > </table> > > + <note> > <para> > ! Prior to PostgreSQL 8.2, the containment operators <literal>@></> > ! and <literal><@</> were called <literal>@</> and <literal>~</>, > ! respectively. These names are still available, but are deprecated and will > ! eventually be removed. Notice that the old names are reversed from the > ! convention formerly followed by the core geometric datatypes! > ! </para> > ! </note> > > <table id="hstore-func-table"> > <title><type>hstore</> Functions</title> > *************** > *** 251,257 **** > <row> > <entry><function>akeys(hstore)</function></entry> > <entry><type>text[]</type></entry> > ! <entry>get <type>hstore</>'s keys as array</entry> > <entry><literal>akeys('a=>1,b=>2')</literal></entry> > <entry><literal>{a,b}</literal></entry> > </row> > --- 267,273 ---- > <row> > <entry><function>akeys(hstore)</function></entry> > <entry><type>text[]</type></entry> > ! <entry>get <type>hstore</>'s keys as an array</entry> > <entry><literal>akeys('a=>1,b=>2')</literal></entry> > <entry><literal>{a,b}</literal></entry> > </row> > *************** > *** 259,268 **** > <row> > <entry><function>skeys(hstore)</function></entry> > <entry><type>setof text</type></entry> > ! <entry>get <type>hstore</>'s keys as set</entry> > <entry><literal>skeys('a=>1,b=>2')</literal></entry> > <entry> > ! <programlisting> > a > b > </programlisting></entry> > --- 275,284 ---- > <row> > <entry><function>skeys(hstore)</function></entry> > <entry><type>setof text</type></entry> > ! <entry>get <type>hstore</>'s keys as a set</entry> > <entry><literal>skeys('a=>1,b=>2')</literal></entry> > <entry> > ! 22<programlisting> > a > b > </programlisting></entry> > *************** b > *** 271,277 **** > <row> > <entry><function>avals(hstore)</function></entry> > <entry><type>text[]</type></entry> > ! <entry>get <type>hstore</>'s values as array</entry> > <entry><literal>avals('a=>1,b=>2')</literal></entry> > <entry><literal>{1,2}</literal></entry> > </row> > --- 287,293 ---- > <row> > <entry><function>avals(hstore)</function></entry> > <entry><type>text[]</type></entry> > ! <entry>get <type>hstore</>'s values as an array</entry> > <entry><literal>avals('a=>1,b=>2')</literal></entry> > <entry><literal>{1,2}</literal></entry> > </row> > *************** b > *** 279,285 **** > <row> > <entry><function>svals(hstore)</function></entry> > <entry><type>setof text</type></entry> > ! <entry>get <type>hstore</>'s values as set</entry> > <entry><literal>svals('a=>1,b=>2')</literal></entry> > <entry> > <programlisting> > --- 295,301 ---- > <row> > <entry><function>svals(hstore)</function></entry> > <entry><type>setof text</type></entry> > ! <entry>get <type>hstore</>'s values as a set</entry> > <entry><literal>svals('a=>1,b=>2')</literal></entry> > <entry> > <programlisting> > *************** b > *** 307,314 **** > > <row> > <entry><function>each(hstore)</function></entry> > ! <entry><type>setof (key text, value text)</type></entry> > ! <entry>get <type>hstore</>'s keys and values as set</entry> > <entry><literal>select * from each('a=>1,b=>2')</literal></entry> > <entry> > <programlisting> > --- 323,330 ---- > > <row> > <entry><function>each(hstore)</function></entry> > ! <entry><type>setof <literal>(key text, value text)</></type></entry> > ! <entry>get <type>hstore</>'s keys and values as a set</entry> > <entry><literal>select * from each('a=>1,b=>2')</literal></entry> > <entry> > <programlisting> > *************** b > *** 330,336 **** > <row> > <entry><function>defined(hstore,text)</function></entry> > <entry><type>boolean</type></entry> > ! <entry>does <type>hstore</> contain non-null value for key?</entry> > <entry><literal>defined('a=>NULL','a')</literal></entry> > <entry><literal>f</literal></entry> > </row> > --- 346,352 ---- > <row> > <entry><function>defined(hstore,text)</function></entry> > <entry><type>boolean</type></entry> > ! <entry>does <type>hstore</> contain non-<literal>NULL</> value for key?</entry> > <entry><literal>defined('a=>NULL','a')</literal></entry> > <entry><literal>f</literal></entry> > </row> > *************** b > *** 338,344 **** > <row> > <entry><function>delete(hstore,text)</function></entry> > <entry><type>hstore</type></entry> > ! <entry>delete any item matching key</entry> > <entry><literal>delete('a=>1,b=>2','b')</literal></entry> > <entry><literal>"a"=>"1"</literal></entry> > </row> > --- 354,360 ---- > <row> > <entry><function>delete(hstore,text)</function></entry> > <entry><type>hstore</type></entry> > ! <entry>delete pair with matching key</entry> > <entry><literal>delete('a=>1,b=>2','b')</literal></entry> > <entry><literal>"a"=>"1"</literal></entry> > </row> > *************** b > *** 346,352 **** > <row> > <entry><function>delete(hstore,text[])</function></entry> > <entry><type>hstore</type></entry> > ! <entry>delete any item matching any of the keys</entry> > <entry><literal>delete('a=>1,b=>2,c=>3',ARRAY['a','b'])</literal></entry> > <entry><literal>"c"=>"3"</literal></entry> > </row> > --- 362,368 ---- > <row> > <entry><function>delete(hstore,text[])</function></entry> > <entry><type>hstore</type></entry> > ! <entry>delete pairs with matching keys</entry> > <entry><literal>delete('a=>1,b=>2,c=>3',ARRAY['a','b'])</literal></entry> > <entry><literal>"c"=>"3"</literal></entry> > </row> > *************** b > *** 354,360 **** > <row> > <entry><function>delete(hstore,hstore)</function></entry> > <entry><type>hstore</type></entry> > ! <entry>delete any key/value pair with an exact match in the second argument</entry> > <entry><literal>delete('a=>1,b=>2','a=>4,b=>2'::hstore)</literal></entry> > <entry><literal>"a"=>"1"</literal></entry> > </row> > --- 370,376 ---- > <row> > <entry><function>delete(hstore,hstore)</function></entry> > <entry><type>hstore</type></entry> > ! <entry>delete pairs matching those in the second argument</entry> > <entry><literal>delete('a=>1,b=>2','a=>4,b=>2'::hstore)</literal></entry> > <entry><literal>"a"=>"1"</literal></entry> > </row> > *************** b > *** 362,368 **** > <row> > <entry><function>populate_record(record,hstore)</function></entry> > <entry><type>record</type></entry> > ! <entry>replace fields in record with matching values from hstore</entry> > <entry>see Examples section</entry> > <entry></entry> > </row> > --- 378,384 ---- > <row> > <entry><function>populate_record(record,hstore)</function></entry> > <entry><type>record</type></entry> > ! <entry>replace fields in <type>record</> with matching values from <type>hstore</></entry> > <entry>see Examples section</entry> > <entry></entry> > </row> > *************** b > *** 374,380 **** > <note> > <para> > The function <function>populate_record</function> is actually declared > ! with <type>anyelement</>, not <type>record</>, as its first argument; > but it will reject non-record types with a runtime error. > </para> > </note> > --- 390,396 ---- > <note> > <para> > The function <function>populate_record</function> is actually declared > ! with <type>anyelement</>, not <type>record</>, as its first argument, > but it will reject non-record types with a runtime error. > </para> > </note> > *************** b > *** 384,392 **** > <title>Indexes</title> > > <para> > ! <type>hstore</> has index support for <literal>@></>, <literal>?</>, > ! <literal>?&</> and <literal>?|</> operators. You can use either > ! GiST or GIN index types. For example: > </para> > <programlisting> > CREATE INDEX hidx ON testhstore USING GIST (h); > --- 400,407 ---- > <title>Indexes</title> > > <para> > ! <type>hstore</> has GiST and GIN index support for the <literal>@></>, > ! <literal>?</>, <literal>?&</> and <literal>?|</> operators. For example: > </para> > <programlisting> > CREATE INDEX hidx ON testhstore USING GIST (h); > *************** CREATE INDEX hidx ON testhstore USING GI > *** 395,408 **** > </programlisting> > > <para> > ! Additionally, <type>hstore</> has index support for the <literal>=</> > ! operator using the <type>btree</> or <type>hash</> index types. This > ! allows <type>hstore</> columns to be declared UNIQUE, or used with > ! GROUP BY, ORDER BY or DISTINCT. The sort ordering for <type>hstore</> > ! values is not intended to be particularly useful; it merely brings > ! exactly equal values together. > ! If an index is needed to support <literal>=</> comparisons it can be > ! created as follows: > </para> > <programlisting> > CREATE INDEX hidx ON testhstore USING BTREE (h); > --- 410,422 ---- > </programlisting> > > <para> > ! <type>hstore</> also supports <type>btree</> or <type>hash</> indexes for > ! the <literal>=</> operator. This allows <type>hstore</> columns to be > ! declared <literal>UNIQUE</>, or to be used in <literal>GROUP BY</>, > ! <literal>ORDER BY</> or <literal>DISTINCT</> expressions. The sort ordering > ! for <type>hstore</> values is not particularly useful, but these indexes > ! may be useful for equivalence lookups. Create indexes for <literal>=</> > ! comparisons as follows: > </para> > <programlisting> > CREATE INDEX hidx ON testhstore USING BTREE (h); > *************** CREATE INDEX hidx ON testhstore USING HA > *** 418,424 **** > Add a key, or update an existing key with a new value: > </para> > <programlisting> > ! UPDATE tab SET h = h || ('c' => '3'); > </programlisting> > > <para> > --- 432,438 ---- > Add a key, or update an existing key with a new value: > </para> > <programlisting> > ! UPDATE tab SET h = h || ('c' => '3'); > </programlisting> > > <para> > *************** UPDATE tab SET h = delete(h, 'k1'); > *** 429,435 **** > </programlisting> > > <para> > ! Convert a record to an hstore: > </para> > <programlisting> > CREATE TABLE test (col1 integer, col2 text, col3 text); > --- 443,449 ---- > </programlisting> > > <para> > ! Convert a <type>record</> to an <type>hstore</>: > </para> > <programlisting> > CREATE TABLE test (col1 integer, col2 text, col3 text); > *************** INSERT INTO test VALUES (123, 'foo', 'ba > *** 438,455 **** > SELECT hstore(t) FROM test AS t; > hstore > --------------------------------------------- > ! "col1"=>"123", "col2"=>"foo", "col3"=>"bar" > (1 row) > </programlisting> > > <para> > ! Convert an hstore to a predefined record type: > </para> > <programlisting> > CREATE TABLE test (col1 integer, col2 text, col3 text); > > SELECT * FROM populate_record(null::test, > ! '"col1"=>"456", "col2"=>"zzz"'); > col1 | col2 | col3 > ------+------+------ > 456 | zzz | > --- 452,469 ---- > SELECT hstore(t) FROM test AS t; > hstore > --------------------------------------------- > ! "col1"=>"123", "col2"=>"foo", "col3"=>"bar" > (1 row) > </programlisting> > > <para> > ! Convert an <type>hstore</> to a predefined <type>record</> type: > </para> > <programlisting> > CREATE TABLE test (col1 integer, col2 text, col3 text); > > SELECT * FROM populate_record(null::test, > ! '"col1"=>"456", "col2"=>"zzz"'); > col1 | col2 | col3 > ------+------+------ > 456 | zzz | > *************** SELECT * FROM populate_record(null::test > *** 457,469 **** > </programlisting> > > <para> > ! Modify an existing record using the values from an hstore: > </para> > <programlisting> > CREATE TABLE test (col1 integer, col2 text, col3 text); > INSERT INTO test VALUES (123, 'foo', 'bar'); > > ! SELECT (r).* FROM (SELECT t #= '"col3"=>"baz"' AS r FROM test t) s; > col1 | col2 | col3 > ------+------+------ > 123 | foo | baz > --- 471,483 ---- > </programlisting> > > <para> > ! Modify an existing record using the values from an <type>hstore</>: > </para> > <programlisting> > CREATE TABLE test (col1 integer, col2 text, col3 text); > INSERT INTO test VALUES (123, 'foo', 'bar'); > > ! SELECT (r).* FROM (SELECT t #= '"col3"=>"baz"' AS r FROM test t) s; > col1 | col2 | col3 > ------+------+------ > 123 | foo | baz > *************** SELECT (r).* FROM (SELECT t #= '"col3"=> > *** 477,491 **** > <para> > The <type>hstore</> type, because of its intrinsic liberality, could > contain a lot of different keys. Checking for valid keys is the task of the > ! application. Examples below demonstrate several techniques for checking > ! keys and obtaining statistics. > </para> > > <para> > Simple example: > </para> > <programlisting> > ! SELECT * FROM each('aaa=>bq, b=>NULL, ""=>1'); > </programlisting> > > <para> > --- 491,505 ---- > <para> > The <type>hstore</> type, because of its intrinsic liberality, could > contain a lot of different keys. Checking for valid keys is the task of the > ! application. The following examples demonstrate several techniques for > ! checking keys and obtaining statistics. > </para> > > <para> > Simple example: > </para> > <programlisting> > ! SELECT * FROM each('aaa=>bq, b=>NULL, ""=>1'); > </programlisting> > > <para> > *************** SELECT key, count(*) FROM > *** 523,530 **** > > <para> > <emphasis>When upgrading from older versions, always load the new > ! version of this module into the database before restoring an old > ! dump. Otherwise, many new features will be unavailable.</emphasis> > </para> > > <para> > --- 537,544 ---- > > <para> > <emphasis>When upgrading from older versions, always load the new > ! version of this module into the database before restoring a dump. > ! Otherwise, many new features will be unavailable.</emphasis> > </para> > > <para> > *************** SELECT key, count(*) FROM > *** 535,546 **** > </para> > > <para> > ! In the event of doing a binary upgrade, upward > ! compatibility is maintained by having the new code recognize > ! old-format data. This will entail a slight performance penalty when > ! processing data that has not yet been modified by the new code. It is > ! possible to force an upgrade of all values in a table column > ! by doing an UPDATE statement as follows: > </para> > <programlisting> > UPDATE tablename SET hstorecol = hstorecol || ''; > --- 549,559 ---- > </para> > > <para> > ! In the event of a binary upgrade, upward compatibility is maintained by > ! having the new code recognize old-format data. This will entail a slight > ! performance penalty when processing data that has not yet been modified by > ! the new code. It is possible to force an upgrade of all values in a table > ! column by doing an <literal>UPDATE</> statement as follows: > </para> > <programlisting> > UPDATE tablename SET hstorecol = hstorecol || ''; > *************** ALTER TABLE tablename ALTER hstorecol TY > *** 569,575 **** > </para> > > <para> > ! Additional enhancements by Andrew Gierth <email>andrew(a)tao11.riddles.org.uk</email>, United Kingdom > </para> > </sect2> > > --- 582,589 ---- > </para> > > <para> > ! Additional enhancements by Andrew Gierth <email>andrew(a)tao11.riddles.org.uk</email>, > ! United Kingdom > </para> > </sect2> > > -- > 1.6.4 > > -- > Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-hackers -- Bruce Momjian <bruce(a)momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + If your life is a hard drive, Christ can be your backup. + -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
From: "David E. Wheeler" on 30 Nov 2009 13:01 On Dec 1, 2009, at 2:56 AM, Bruce Momjian wrote: > Applied. Thanks. Thanks, I'll remove it from the next CF list, then. Best, David -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
From: "David E. Wheeler" on 30 Nov 2009 13:02 On Dec 1, 2009, at 3:01 AM, David E. Wheeler wrote: > On Dec 1, 2009, at 2:56 AM, Bruce Momjian wrote: > >> Applied. Thanks. > > Thanks, I'll remove it from the next CF list, then. Oh, you already marked it as committed. Thanks! David -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
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