The result of a subscripting expression is always of the jsonb data type.
</para>
+ <para>
+ <command>UPDATE</command> statements may use subscripting in the
+ <literal>SET</literal> clause to modify <type>jsonb</type> values. Subscript
+ paths must be traversible for all affected values insofar as they exist. For
+ instance, the path <literal>val['a']['b']['c']</literal> can be traversed all
+ the way to <literal>c</literal> if every <literal>val</literal>,
+ <literal>val['a']</literal>, and <literal>val['a']['b']</literal> is an
+ object. If any <literal>val['a']</literal> or <literal>val['a']['b']</literal>
+ is not defined, it will be created as an empty object and filled as
+ necessary. However, if any <literal>val</literal> itself or one of the
+ intermediary values is defined as a non-object such as a string, number, or
+ <literal>jsonb</literal> <literal>null</literal>, traversal cannot proceed so
+ an error is raised and the transaction aborted.
+ </para>
+
<para>
An example of subscripting syntax:
+
<programlisting>
-- Extract object value by key
-- value must be of the jsonb type as well
UPDATE table_name SET jsonb_field['key'] = '1';
+-- This will raise an error if any record's jsonb_field['a']['b'] is something
+-- other than an object. For example, the value {"a": 1} has no 'b' key.
+UPDATE table_name SET jsonb_field['a']['b']['c'] = '1';
+
-- Filter records using a WHERE clause with subscripting. Since the result of
-- subscripting is jsonb, the value we compare it against must also be jsonb.
-- The double quotes make "value" also a valid jsonb string.
<type>jsonb</type> assignment via subscripting handles a few edge cases
differently from <literal>jsonb_set</literal>. When a source <type>jsonb</type>
- is <literal>NULL</literal>, assignment via subscripting will proceed as if
- it was an empty JSON object:
+ value is <literal>NULL</literal>, assignment via subscripting will proceed
+ as if it was an empty JSON value of the type (object or array) implied by the
+ subscript key:
<programlisting>
-- Where jsonb_field was NULL, it is now {"a": 1}
</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.
+ paths as long as the last existing element to be traversed is an object or
+ array, as implied by the corresponding subscript (the element indicated by
+ the last subscript in the path is not traversed and may be anything). Nested
+ array and object structures will be created, and in the former case
+ <literal>null</literal>-padded, as specified by the subscript path until the
+ assigned value can be placed.
<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';
+-- Where jsonb_field was [], it is now [null, {'a': 1}]
+UPDATE table_name SET jsonb_field[1]['a'] = '1';
</programlisting>
</para>
switch (r)
{
case WJB_BEGIN_ARRAY:
+
+ /*
+ * If instructed complain about attempts to replace whithin a raw
+ * scalar value. This happens even when current level is equal to
+ * path_len, because the last path key should also correspond to
+ * an object or an array, not raw scalar.
+ */
+ if ((op_type & JB_PATH_FILL_GAPS) && (level <= path_len - 1) &&
+ v.val.array.rawScalar)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("cannot replace existing key"),
+ errdetail("The path assumes key is a composite object, "
+ "but it is a scalar value.")));
+
(void) pushJsonbValue(st, r, NULL);
setPathArray(it, path_elems, path_nulls, path_len, st, level,
newval, v.val.array.nElems, op_type);
break;
case WJB_ELEM:
case WJB_VALUE:
+
+ /*
+ * If instructed complain about attempts to replace whithin a
+ * scalar value. This happens even when current level is equal to
+ * path_len, because the last path key should also correspond to
+ * an object or an array, not an element or value.
+ */
+ if ((op_type & JB_PATH_FILL_GAPS) && (level <= path_len - 1))
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("cannot replace existing key"),
+ errdetail("The path assumes key is a composite object, "
+ "but it is a scalar value.")));
+
res = pushJsonbValue(st, r, &v);
break;
default:
1 | {"a": [null, {"c": [null, null, 1]}]}
(1 row)
+-- trying replace assuming a composite object, but it's an element or a value
+delete from test_jsonb_subscript;
+insert into test_jsonb_subscript values (1, '{"a": 1}');
+update test_jsonb_subscript set test_json['a']['b'] = '1';
+ERROR: cannot replace existing key
+DETAIL: The path assumes key is a composite object, but it is a scalar value.
+update test_jsonb_subscript set test_json['a']['b']['c'] = '1';
+ERROR: cannot replace existing key
+DETAIL: The path assumes key is a composite object, but it is a scalar value.
+update test_jsonb_subscript set test_json['a'][0] = '1';
+ERROR: cannot replace existing key
+DETAIL: The path assumes key is a composite object, but it is a scalar value.
+update test_jsonb_subscript set test_json['a'][0]['c'] = '1';
+ERROR: cannot replace existing key
+DETAIL: The path assumes key is a composite object, but it is a scalar value.
+update test_jsonb_subscript set test_json['a'][0][0] = '1';
+ERROR: cannot replace existing key
+DETAIL: The path assumes key is a composite object, but it is a scalar value.
+-- trying replace assuming a composite object, but it's a raw scalar
+delete from test_jsonb_subscript;
+insert into test_jsonb_subscript values (1, 'null');
+update test_jsonb_subscript set test_json[0] = '1';
+ERROR: cannot replace existing key
+DETAIL: The path assumes key is a composite object, but it is a scalar value.
+update test_jsonb_subscript set test_json[0][0] = '1';
+ERROR: cannot replace existing key
+DETAIL: The path assumes key is a composite object, but it is a scalar value.
-- jsonb to tsvector
select to_tsvector('{"a": "aaa bbb ddd ccc", "b": ["eee fff ggg"], "c": {"d": "hhh iii"}}'::jsonb);
to_tsvector
update test_jsonb_subscript set test_json['a'][1]['c'][2] = '1';
select * from test_jsonb_subscript;
+-- trying replace assuming a composite object, but it's an element or a value
+
+delete from test_jsonb_subscript;
+insert into test_jsonb_subscript values (1, '{"a": 1}');
+update test_jsonb_subscript set test_json['a']['b'] = '1';
+update test_jsonb_subscript set test_json['a']['b']['c'] = '1';
+update test_jsonb_subscript set test_json['a'][0] = '1';
+update test_jsonb_subscript set test_json['a'][0]['c'] = '1';
+update test_jsonb_subscript set test_json['a'][0][0] = '1';
+
+-- trying replace assuming a composite object, but it's a raw scalar
+
+delete from test_jsonb_subscript;
+insert into test_jsonb_subscript values (1, 'null');
+update test_jsonb_subscript set test_json[0] = '1';
+update test_jsonb_subscript set test_json[0][0] = '1';
+
-- jsonb to tsvector
select to_tsvector('{"a": "aaa bbb ddd ccc", "b": ["eee fff ggg"], "c": {"d": "hhh iii"}}'::jsonb);
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