Map PG jsonb to SQL JSON type

Author: Nikita Glukhov

doc/src/sgml/config.sgml

@@ -9510,6 +9510,23 @@ dynamic_library_path = 'C:\tools\postgresql;H:\my_project\lib;$libdir'
       </listitem>
      </varlistentry>
 
+     <varlistentry id="guc-json-as-jsonb" xreflabel="json_as_jsonb">
+      <term><varname>json_as_jsonb</varname> (<type>boolean</type>)
+      <indexterm><primary>json</primary></indexterm>
+      <indexterm><primary>jsonb</primary></indexterm>
+      <indexterm>
+       <primary><varname>json_as_jsonb</varname> configuration parameter</primary>
+      </indexterm>
+      </term>
+      <listitem>
+       <para>
+         When on, SQL type <type>JSON</type> is mapped to
+         <productname>PostgreSQL</productname> type <type>jsonb</type>.
+         But SQL type <type>JSON TEXT</type> is always mapped to
+         <productname>PostgreSQL</productname> type <type>json</type>.
+       </para>
+      </listitem>
+     </varlistentry>
      </variablelist>
     </sect2>
    </sect1>

src/backend/parser/gram.y

@@ -63,6 +63,7 @@
 #include "storage/lmgr.h"
 #include "utils/date.h"
 #include "utils/datetime.h"
+#include "utils/jsonb.h"
 #include "utils/numeric.h"
 #include "utils/xml.h"
 
@@ -527,7 +528,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <list>	copy_options
 
 %type <typnam>	Typename SimpleTypename ConstTypename
-				GenericType Numeric opt_float
+				GenericType Numeric opt_float JsonType
 				Character ConstCharacter
 				CharacterWithLength CharacterWithoutLength
 				ConstDatetime ConstInterval
@@ -663,7 +664,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	INNER_P INOUT INPUT_P INSENSITIVE INSERT INSTEAD INT_P INTEGER
 	INTERSECT INTERVAL INTO INVOKER IS ISNULL ISOLATION
 
-	JOIN
+	JOIN JSON
 
 	KEY
 
@@ -775,6 +776,8 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %left		'*' '/' '%'
 %left		'^'
 /* Unary Operators */
+%nonassoc	JSON
+%left		TEXT_P			/* sets precedence for JSON TEXT */
 %left		AT				/* sets precedence for AT TIME ZONE */
 %left		COLLATE
 %right		UMINUS
@@ -12545,6 +12548,7 @@ SimpleTypename:
 					$$->typmods = list_make2(makeIntConst(INTERVAL_FULL_RANGE, -1),
 											 makeIntConst($3, @3));
 				}
+			| JsonType								{ $$ = $1; }
 		;
 
 /* We have a separate ConstTypename to allow defaulting fixed-length
@@ -12560,6 +12564,7 @@ SimpleTypename:
  */
 ConstTypename:
 			Numeric									{ $$ = $1; }
+			| JsonType								{ $$ = $1; }
 			| ConstBit								{ $$ = $1; }
 			| ConstCharacter						{ $$ = $1; }
 			| ConstDatetime							{ $$ = $1; }
@@ -12931,6 +12936,20 @@ interval_second:
 				}
 		;
 
+/* Mapping of PG jsonb types to SQL/JSON JSON type */
+JsonType:
+			JSON
+				{
+					$$ = SystemTypeName(json_as_jsonb ? "jsonb" : "json");
+					$$->location = @1;
+				}
+			| JSON TEXT_P
+				{
+					$$ = SystemTypeName("json");
+					$$->location = @1;
+				}
+		;
+
 
 /*****************************************************************************
  *
@@ -13623,6 +13642,12 @@ c_expr:		columnref								{ $$ = $1; }
 				  g->location = @1;
 				  $$ = (Node *)g;
 			  }
+			| JSON '(' a_expr ')'
+				{
+					List	   *typname = list_make1(makeString(json_as_jsonb ? "jsonb" : "json"));
+
+					$$ = (Node *) makeFuncCall(typname, list_make1($3), COERCE_EXPLICIT_CALL, @1);
+				}
 		;
 
 func_application: func_name '(' ')'
@@ -15468,6 +15493,7 @@ col_name_keyword:
 			| INT_P
 			| INTEGER
 			| INTERVAL
+			| JSON
 			| LEAST
 			| NATIONAL
 			| NCHAR
@@ -15813,6 +15839,7 @@ bare_label_keyword:
 			| IS
 			| ISOLATION
 			| JOIN
+			| JSON
 			| KEY
 			| LABEL
 			| LANGUAGE

src/backend/utils/adt/format_type.c

@@ -22,6 +22,7 @@
 #include "catalog/pg_type.h"
 #include "mb/pg_wchar.h"
 #include "utils/builtins.h"
+#include "utils/jsonb.h"
 #include "utils/lsyscache.h"
 #include "utils/numeric.h"
 #include "utils/syscache.h"
@@ -294,6 +295,14 @@ format_type_extended(Oid type_oid, int32 typemod, bits16 flags)
 			else
 				buf = pstrdup("character varying");
 			break;
+
+		case JSONBOID:
+			buf = pstrdup(json_as_jsonb ? "json" : "jsonb");
+			break;
+
+		case JSONOID:
+			buf = pstrdup(json_as_jsonb ? "json text" : "json");
+			break;
 	}
 
 	if (buf == NULL)

src/backend/utils/adt/jsonb.c

@@ -100,6 +100,8 @@ static char *JsonbToCStringWorker(StringInfo out, JsonbContainer *in,
 								  int estimated_len, JsonFormat format);
 static void add_indent(StringInfo out, bool indent, int level);
 
+bool json_as_jsonb;		/* GUC for mapping jsonb to SQL/JSON JSON */
+
 /*
  * jsonb type input function
  */

src/backend/utils/misc/guc.c

@@ -90,6 +90,7 @@
 #include "utils/bytea.h"
 #include "utils/float.h"
 #include "utils/guc_tables.h"
+#include "utils/jsonb.h"
 #include "utils/memutils.h"
 #include "utils/pg_locale.h"
 #include "utils/pg_lsn.h"
@@ -2036,6 +2037,17 @@ static struct config_bool ConfigureNamesBool[] =
 		NULL, NULL, NULL
 	},
 
+	{
+		{"json_as_jsonb", PGC_USERSET, COMPAT_OPTIONS_CLIENT,
+			gettext_noop("Use jsonb type as default implementation of SQL JSON type."),
+			gettext_noop("When turned on, jsonb type is mapped to SQL JSON type, "
+						 "json type is mapped to JSON TEXT type.")
+		},
+		&json_as_jsonb,
+		false,
+		NULL, NULL, NULL
+	},
+
 	/* End-of-list marker */
 	{
 		{NULL, 0, 0, NULL, NULL}, NULL, false, NULL, NULL, NULL

src/include/parser/kwlist.h

@@ -221,6 +221,7 @@ PG_KEYWORD("is", IS, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL)
 PG_KEYWORD("isnull", ISNULL, TYPE_FUNC_NAME_KEYWORD, AS_LABEL)
 PG_KEYWORD("isolation", ISOLATION, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("join", JOIN, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL)
+PG_KEYWORD("json", JSON, COL_NAME_KEYWORD, BARE_LABEL)
 PG_KEYWORD("key", KEY, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("label", LABEL, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("language", LANGUAGE, UNRESERVED_KEYWORD, BARE_LABEL)

src/include/utils/jsonb.h

@@ -402,5 +402,6 @@ extern void JsonbHashScalarValueExtended(const JsonbValue *scalarVal,
 extern int reserveFromBuffer(StringInfo buffer, int len);
 extern void appendToBuffer(StringInfo buffer, const void *data, int len);
 
+extern bool json_as_jsonb;	/* GUC */
 
 #endif							/* __JSONB_H__ */

src/test/regress/expected/jsonb.out

@@ -5017,3 +5017,133 @@ select '12345.0000000000000000000000000000000000000000000005'::jsonb::int8;
  12345
 (1 row)
 
+-- test mapping of jsonb to SQL/JSON JSON type
+select json(' { "aa": 1, "b" : 2 }');
+         json          
+-----------------------
+  { "aa": 1, "b" : 2 }
+(1 row)
+
+select json ' { "aa": 1, "b" : 2 }';
+         json          
+-----------------------
+  { "aa": 1, "b" : 2 }
+(1 row)
+
+select json text ' { "aa": 1, "b" : 2 }';
+         json          
+-----------------------
+  { "aa": 1, "b" : 2 }
+(1 row)
+
+create table test_json_as_json (js json, jb jsonb);
+\d test_json_as_json
+        Table "public.test_json_as_json"
+ Column | Type  | Collation | Nullable | Default 
+--------+-------+-----------+----------+---------
+ js     | json  |           |          | 
+ jb     | jsonb |           |          | 
+
+set json_as_jsonb = on;
+select json(' { "aa": 1, "b" : 2 }');
+       jsonb       
+-------------------
+ {"b": 2, "aa": 1}
+(1 row)
+
+select json ' { "aa": 1, "b" : 2 }';
+       jsonb       
+-------------------
+ {"b": 2, "aa": 1}
+(1 row)
+
+select json text ' { "aa": 1, "b" : 2 }';
+         json          
+-----------------------
+  { "aa": 1, "b" : 2 }
+(1 row)
+
+\d test_json_as_json
+          Table "public.test_json_as_json"
+ Column |   Type    | Collation | Nullable | Default 
+--------+-----------+-----------+----------+---------
+ js     | json text |           |          | 
+ jb     | json      |           |          | 
+
+create table test_json_as_jsonb (js json, jb jsonb, jt json text);
+\d test_json_as_jsonb
+          Table "public.test_json_as_jsonb"
+ Column |   Type    | Collation | Nullable | Default 
+--------+-----------+-----------+----------+---------
+ js     | json      |           |          | 
+ jb     | json      |           |          | 
+ jt     | json text |           |          | 
+
+insert into test_json_as_jsonb values ('{ "a" : 1 }', '{ "a" : 1 }', '{ "a" : 1 }');
+select * from test_json_as_jsonb;
+    js    |    jb    |     jt      
+----------+----------+-------------
+ {"a": 1} | {"a": 1} | { "a" : 1 }
+(1 row)
+
+select jsonb_object_field(js, 'a') from test_json_as_jsonb;
+ jsonb_object_field 
+--------------------
+ 1
+(1 row)
+
+select jsonb_object_field(jb, 'a') from test_json_as_jsonb;
+ jsonb_object_field 
+--------------------
+ 1
+(1 row)
+
+select jsonb_object_field(jt, 'a') from test_json_as_jsonb;
+ERROR:  function jsonb_object_field(json text, unknown) does not exist
+LINE 1: select jsonb_object_field(jt, 'a') from test_json_as_jsonb;
+               ^
+HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+select json_object_field(jt, 'a') from test_json_as_jsonb;
+ json_object_field 
+-------------------
+ 1
+(1 row)
+
+set json_as_jsonb = off;
+\d test_json_as_jsonb
+        Table "public.test_json_as_jsonb"
+ Column | Type  | Collation | Nullable | Default 
+--------+-------+-----------+----------+---------
+ js     | jsonb |           |          | 
+ jb     | jsonb |           |          | 
+ jt     | json  |           |          | 
+
+select * from test_json_as_jsonb;
+    js    |    jb    |     jt      
+----------+----------+-------------
+ {"a": 1} | {"a": 1} | { "a" : 1 }
+(1 row)
+
+select jsonb_object_field(js, 'a') from test_json_as_jsonb;
+ jsonb_object_field 
+--------------------
+ 1
+(1 row)
+
+select jsonb_object_field(jb, 'a') from test_json_as_jsonb;
+ jsonb_object_field 
+--------------------
+ 1
+(1 row)
+
+select jsonb_object_field(jt, 'a') from test_json_as_jsonb;
+ERROR:  function jsonb_object_field(json, unknown) does not exist
+LINE 1: select jsonb_object_field(jt, 'a') from test_json_as_jsonb;
+               ^
+HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+select json_object_field(jt, 'a') from test_json_as_jsonb;
+ json_object_field 
+-------------------
+ 1
+(1 row)
+

src/test/regress/sql/jsonb.sql

@@ -1280,3 +1280,41 @@ select '12345.0000000000000000000000000000000000000000000005'::jsonb::float8;
 select '12345.0000000000000000000000000000000000000000000005'::jsonb::int2;
 select '12345.0000000000000000000000000000000000000000000005'::jsonb::int4;
 select '12345.0000000000000000000000000000000000000000000005'::jsonb::int8;
+
+-- test mapping of jsonb to SQL/JSON JSON type
+select json(' { "aa": 1, "b" : 2 }');
+select json ' { "aa": 1, "b" : 2 }';
+select json text ' { "aa": 1, "b" : 2 }';
+
+create table test_json_as_json (js json, jb jsonb);
+\d test_json_as_json
+
+set json_as_jsonb = on;
+
+select json(' { "aa": 1, "b" : 2 }');
+select json ' { "aa": 1, "b" : 2 }';
+select json text ' { "aa": 1, "b" : 2 }';
+
+\d test_json_as_json
+
+create table test_json_as_jsonb (js json, jb jsonb, jt json text);
+\d test_json_as_jsonb
+
+insert into test_json_as_jsonb values ('{ "a" : 1 }', '{ "a" : 1 }', '{ "a" : 1 }');
+
+select * from test_json_as_jsonb;
+
+select jsonb_object_field(js, 'a') from test_json_as_jsonb;
+select jsonb_object_field(jb, 'a') from test_json_as_jsonb;
+select jsonb_object_field(jt, 'a') from test_json_as_jsonb;
+select json_object_field(jt, 'a') from test_json_as_jsonb;
+
+set json_as_jsonb = off;
+\d test_json_as_jsonb
+
+select * from test_json_as_jsonb;
+
+select jsonb_object_field(js, 'a') from test_json_as_jsonb;
+select jsonb_object_field(jb, 'a') from test_json_as_jsonb;
+select jsonb_object_field(jt, 'a') from test_json_as_jsonb;
+select json_object_field(jt, 'a') from test_json_as_jsonb;