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Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/json.sgml | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/doc/src/sgml/json.sgml b/doc/src/sgml/json.sgml index 3ace5e444b0..07bd19f9742 100644 --- a/doc/src/sgml/json.sgml +++ b/doc/src/sgml/json.sgml @@ -650,6 +650,30 @@ UPDATE table_name SET jsonb_field['a'] = '1'; UPDATE table_name SET jsonb_field[0] = '1'; </programlisting> + If an index is specified for an array containing too few elements, + <literal>NULL</literal> elements will be appended until the index is reachable + and the value can be set. + +<programlisting> +-- Where jsonb_field was [], it is now [null, null, 2]; +-- where jsonb_field was [0], it is now [0, null, 2] +UPDATE table_name SET jsonb_field[2] = '2'; +</programlisting> + + A <type>jsonb</type> value will accept assignments to nonexistent subscript + paths as long as the last existing path key is an object or an array. Since + the final subscript is not traversed, it may be an object key. Nested arrays + will be created and <literal>NULL</literal>-padded according to the path until + the value can be placed appropriately. + +<programlisting> +-- Where jsonb_field was {}, it is now {'a': [{'b': 1}]} +UPDATE table_name SET jsonb_field['a'][0]['b'] = '1'; + +-- Where jsonb_field was [], it is now [{'a': 1}] +UPDATE table_name SET jsonb_field[0]['a'] = '1'; +</programlisting> + </para> </sect2> |