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Documentation improvements to jsonpath 

Besides cosmetic improvements it removes statement that operators necessary
need to be separated from operands with spaces, which is not really true.

Discussion: https://postgr.es/m/CAEkD-mDUZrRE%3Dk-FznEg4Ed2VdjpZCyHoyo%2Bp0%2B8KvHqR%3DpNVQ%40mail.gmail.com
Author: Liudmila Mantrova, Alexander Lakhin
Reviewed-by: Alexander Korotkov, Alvaro Herrera
Backpatch-through: 12
This commit is contained in:
Alexander Korotkov 2019-09-13 17:12:20 +03:00
parent fc16778873
commit c30fc9ddd5
2 changed files with 24 additions and 27 deletions
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41
doc/src/sgml/func.sgml
View File

@ -11574,7 +11574,7 @@ table2-mapping
<para>JSON query functions and operators
pass the provided path expression to the <firstterm>path engine</firstterm>
for evaluation. If the expression matches the JSON data to be queried,
for evaluation. If the expression matches the queried JSON data,
the corresponding SQL/JSON item is returned.
Path expressions are written in the SQL/JSON path language
and can also include arithmetic expressions and functions.
@ -11634,7 +11634,7 @@ table2-mapping
<para>
If the item to retrieve is an element of an array, you have
to unnest this array using the [*] operator. For example,
to unnest this array using the <literal>[*]</literal> operator. For example,
the following path will return location coordinates for all
the available track segments:
<programlisting>
@ -11655,8 +11655,7 @@ table2-mapping
The result of each path evaluation step can be processed
by one or more <type>jsonpath</type> operators and methods
listed in <xref linkend="functions-sqljson-path-operators"/>.
Each method must be preceded by a dot, while arithmetic and Boolean
operators are separated from the operands by spaces. For example,
Each method name must be preceded by a dot. For example,
you can get an array size:
<programlisting>
'$.track.segments.size()'
@ -11937,7 +11936,7 @@ table2-mapping
</row>
<row>
<entry><literal>double()</literal></entry>
<entry>Approximate numeric value converted from a string</entry>
<entry>Approximate floating-point number converted from an SQL/JSON number or a string</entry>
<entry><literal>{"len": "1.9"}</literal></entry>
<entry><literal>$.len.double() * 2</literal></entry>
<entry><literal>3.8</literal></entry>
@ -11966,10 +11965,10 @@ table2-mapping
<row>
<entry><literal>keyvalue()</literal></entry>
<entry>
Sequence of object's key-value pairs represented as array of objects
Sequence of object's key-value pairs represented as array of items
containing three fields (<literal>"key"</literal>,
<literal>"value"</literal>, and <literal>"id"</literal>).
<literal>"id"</literal> is an unique identifier of the object
<literal>"id"</literal> is a unique identifier of the object
key-value pair belongs to.
</entry>
<entry><literal>{"x": "20", "y": 32}</literal></entry>
@ -12091,9 +12090,9 @@ table2-mapping
<entry><literal>like_regex</literal></entry>
<entry>
Tests pattern matching with POSIX regular expressions
(<xref linkend="functions-posix-regexp"/>). Supported flags
(see <xref linkend="functions-posix-regexp"/>). Supported flags
are <literal>i</literal>, <literal>s</literal>, <literal>m</literal>,
<literal>x</literal> and <literal>q</literal>.</entry>
<literal>x</literal>, and <literal>q</literal>.</entry>
<entry><literal>["abc", "abd", "aBdC", "abdacb", "babc"]</literal></entry>
<entry><literal>$[*] ? (@ like_regex "^ab.*c" flag "i")</literal></entry>
<entry><literal>"abc", "aBdC", "abdacb"</literal></entry>
@ -12107,7 +12106,7 @@ table2-mapping
</row>
<row>
<entry><literal>exists</literal></entry>
<entry>Tests whether a path expression has at least one SQL/JSON item</entry>
<entry>Tests whether a path expression matches at least one SQL/JSON item</entry>
<entry><literal>{"x": [1, 2], "y": [2, 4]}</literal></entry>
<entry><literal>strict $.* ? (exists (@ ? (@[*] > 2)))</literal></entry>
<entry><literal>2, 4</literal></entry>
@ -12332,10 +12331,9 @@ table2-mapping
<row>
<entry><literal>@@</literal></entry>
<entry><type>jsonpath</type></entry>
<entry>JSON path predicate check result for the specified JSON value.
Only first result item is taken into account. If there are no results
or the first result item is not Boolean, then null
is returned.</entry>
<entry>Returns the result of JSON path predicate check for the specified JSON value.
Only the first item of the result is taken into account. If the
result is not Boolean, then <literal>null</literal> is returned.</entry>
<entry><literal>'{"a":[1,2,3,4,5]}'::jsonb @@ '$.a[*] > 2'</literal></entry>
</row>
</tbody>
@ -12973,7 +12971,7 @@ table2-mapping
<row>
<entry>
<para><literal>
jsonb_path_exists(target jsonb, path jsonpath [, vars jsonb, silent bool])
jsonb_path_exists(target jsonb, path jsonpath [, vars jsonb [, silent bool]])
</literal></para>
</entry>
<entry><type>boolean</type></entry>
@ -12998,10 +12996,9 @@ table2-mapping
</entry>
<entry><type>boolean</type></entry>
<entry>
Returns JSON path predicate result for the specified JSON value.
Only first result item is taken into account. If there are no results
or the first result item is not Boolean, then null
is returned.
Returns the result of JSON path predicate check for the specified JSON value.
Only the first item of the result is taken into account. If the
result is not Boolean, then <literal>null</literal> is returned.
</entry>
<entry>
<para><literal>
@ -13208,18 +13205,18 @@ table2-mapping
<note>
<para>
The <literal>jsonb_path_exists</literal>, <literal>jsonb_path_match</literal>,
<literal>jsonb_path_query</literal>, <literal>jsonb_path_query_array</literal> and
<literal>jsonb_path_query</literal>, <literal>jsonb_path_query_array</literal>, and
<literal>jsonb_path_query_first</literal>
functions have optional <literal>vars</literal> and <literal>silent</literal>
arguments.
</para>
<para>
If the <literal>vars</literal> argument is specified, it provides an
If the <parameter>vars</parameter> argument is specified, it provides an
object containing named variables to be substituted into a
<literal>jsonpath</literal> expression.
</para>
<para>
If the <literal>silent</literal> argument is specified and has the
If the <parameter>silent</parameter> argument is specified and has the
<literal>true</literal> value, these functions suppress the same errors
as the <literal>@?</literal> and <literal>@@</literal> operators.
</para>

10
doc/src/sgml/json.sgml
View File

@ -490,11 +490,11 @@ SELECT jdoc->'guid', jdoc->'name' FROM api WHERE jdoc @@ '$.tags[*] == "qui"';
SELECT jdoc->'guid', jdoc->'name' FROM api WHERE jdoc @@ '$.tags[*] ? (@ == "qui")';
</programlisting>
GIN index extracts statements of following form out of
<literal>jsonpath</literal>: <literal>accessors_chain = const</literal>.
<literal>jsonpath</literal>: <replaceable>accessors_chain</replaceable> = <replaceable>const</replaceable>.
Accessors chain may consist of <literal>.key</literal>,
<literal>[*]</literal> and <literal>[index]</literal> accessors.
<literal>[*]</literal>, and <literal>[<replaceable>index</replaceable>]</literal> accessors.
<literal>jsonb_ops</literal> additionally supports <literal>.*</literal>
and <literal>.**</literal> statements.
and <literal>.**</literal> accessors.
</para>
<para>
Another approach to querying is to exploit containment, for example:
@ -650,12 +650,12 @@ SELECT jdoc-&gt;'guid', jdoc-&gt;'name' FROM api WHERE jdoc @&gt; '{"tags": ["qu
<itemizedlist>
<listitem>
<para>
Dot <literal>.</literal> is used for member access.
Dot (<literal>.</literal>) is used for member access.
</para>
</listitem>
<listitem>
<para>
Square brackets <literal>[]</literal> are used for array access.
Square brackets (<literal>[]</literal>) are used for array access.
</para>
</listitem>
<listitem>