!2329 新增CREATE USER IF NOT EXISTS语法

Merge pull request !2329 from Cross-罗/if_not_exists

doc/src/sgml/ref/create_user.sgmlin

@@ -10,7 +10,7 @@
 </refnamediv>
 <refsynopsisdiv>
 <synopsis>
-CREATE USER user_name [ [ WITH ] option [ ... ] ] [ ENCRYPTED | UNENCRYPTED ] { PASSWORD | IDENTIFIED BY } { 'password' [ EXPIRED ] | DISABLE };
+CREATE USER [IF NOT EXISTS] user_name [ [ WITH ] option [ ... ] ] [ ENCRYPTED | UNENCRYPTED ] { PASSWORD | IDENTIFIED BY } { 'password' [ EXPIRED ] | DISABLE };
 
 where option can be:
 {SYSADMIN | NOSYSADMIN}

src/common/backend/nodes/copyfuncs.cpp

@@ -6086,6 +6086,7 @@ static CreateRoleStmt* _copyCreateRoleStmt(const CreateRoleStmt* from)
 
     COPY_SCALAR_FIELD(stmt_type);
     COPY_STRING_FIELD(role);
+    COPY_SCALAR_FIELD(missing_ok);
     COPY_NODE_FIELD(options);
 
     return newnode;

src/common/backend/nodes/equalfuncs.cpp

@@ -2177,6 +2177,7 @@ static bool _equalCreatePLangStmt(const CreatePLangStmt* a, const CreatePLangStm
 static bool _equalCreateRoleStmt(const CreateRoleStmt* a, const CreateRoleStmt* b)
 {
     COMPARE_SCALAR_FIELD(stmt_type);
+    COMPARE_SCALAR_FIELD(missing_ok);
     COMPARE_STRING_FIELD(role);
     COMPARE_NODE_FIELD(options);
 

src/common/backend/parser/gram.y

@@ -1639,6 +1639,18 @@ CreateUserStmt:
 					IsValidIdentUsername($3);
 					n->role = $3;
 					n->options = $6;
+					n->missing_ok = false;
+					$$ = (Node *)n;
+					u_sess->parser_cxt.isForbidTruncate = false;
+				}
+			| CREATE USER IF_P NOT EXISTS RoleId opt_with {u_sess->parser_cxt.isForbidTruncate = true;} OptRoleList
+				{
+					CreateRoleStmt *n = makeNode(CreateRoleStmt);
+					n->stmt_type = ROLESTMT_USER;
+					IsValidIdentUsername($6);
+					n->role = $6;
+					n->options = $9;
+					n->missing_ok = true;
 					$$ = (Node *)n;
 					u_sess->parser_cxt.isForbidTruncate = false;
 				}
@@ -1831,6 +1843,7 @@ CreateGroupStmt:
 					n->stmt_type = ROLESTMT_GROUP;
 					n->role = $3;
 					n->options = $5;
+					n->missing_ok = false;
 					$$ = (Node *)n;
 				}
 		;

src/gausskernel/optimizer/commands/user.cpp

@@ -1184,7 +1184,12 @@ void CreateRole(CreateRoleStmt* stmt)
 
     if (OidIsValid(get_role_oid(stmt->role, true))) {
         str_reset(password);
-        ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("role \"%s\" already exists", stmt->role)));
+        int elevel = stmt->missing_ok ? NOTICE : ERROR;
+        ereport(elevel, (errmsg("role \"%s\" already exists", stmt->role)));
+        if (stmt->missing_ok) {
+            heap_close(pg_authid_rel, NoLock);
+            return;
+        }
     }
 
     /* Convert validBegin to internal form */

src/include/nodes/parsenodes.h

@@ -1075,6 +1075,7 @@ typedef struct CreateRoleStmt {
     RoleStmtType stmt_type; /* ROLE/USER/GROUP */
     char* role;             /* role name */
     List* options;          /* List of DefElem nodes */
+    bool missing_ok;        /* skip error if a role is exists */
 } CreateRoleStmt;
 
 /* ----------------------

src/test/regress/expected/test_if_not_exists.out

@@ -26,3 +26,10 @@ create user test_user_002 password 'test@1234';
 create schema if not exists test_schema_002 authorization test_user_002;
 drop schema test_schema_002;
 drop user test_user_002;
+CREATE USER ZZZ WITH PASSWORD 'openGauss@123';
+CREATE USER ZZZ WITH PASSWORD 'openGauss@123';
+ERROR:  role "zzz" already exists
+CREATE USER IF NOT EXISTS ZZZ WITH PASSWORD 'openGauss@123';
+NOTICE:  role "zzz" already exists
+DROP USER ZZZ;
+CREATE USER IF NOT EXISTS ZZZ WITH PASSWORD 'openGauss@123';

src/test/regress/sql/test_if_not_exists.sql

@@ -24,3 +24,9 @@ create user test_user_002 password 'test@1234';
 create schema if not exists test_schema_002 authorization test_user_002;
 drop schema test_schema_002;
 drop user test_user_002;
+
+CREATE USER ZZZ WITH PASSWORD 'openGauss@123';
+CREATE USER ZZZ WITH PASSWORD 'openGauss@123';
+CREATE USER IF NOT EXISTS ZZZ WITH PASSWORD 'openGauss@123';
+DROP USER ZZZ;
+CREATE USER IF NOT EXISTS ZZZ WITH PASSWORD 'openGauss@123';