Feature #8062 - CREATE IF NOT EXISTS. (#8072)

doc/sql.extensions/README.ddl.txt

@@ -664,5 +664,43 @@ DROP USER [IF EXISTS] <user> [USING PLUGIN <plugin>]
 DROP PACKAGE [IF EXISTS] <package>
 DROP PACKAGE BODY [IF EXISTS] <package>
 DROP [GLOBAL] MAPPING [IF EXISTS] <mapping>
-ALTER TABLE <table> DROP [IF EXISTS] <column>
+ALTER TABLE <table> DROP [IF EXISTS] <column name>
-ALTER TABLE <table> DROP CONSTRAINT [IF EXISTS] <constraint>
+ALTER TABLE <table> DROP CONSTRAINT [IF EXISTS] <constraint name>
+
+2) CREATE [IF NOT EXISTS]
+
+Using subclause IF NOT EXISTS, it's now possible to try to create objects and do not get errors when they
+already exists.
+
+For ALTER TABLE ... ADD subclause, DDL triggers are not fired if there are only IF NOT EXISTS subclauses and all
+of them are related to existing columns or constraints.
+
+For others commands where IF NOT EXISTS is part of the main command, DDL triggers are not fired when the object
+already exists.
+
+The engine only verifies if the name (object, column or constraint) already exists, and if yes, do nothing.
+It never tries to match the existing object with the one being created.
+
+The following statements are supported:
+
+CREATE EXCEPTION [IF NOT EXISTS] ...
+CREATE INDEX [IF NOT EXISTS] ...
+CREATE PROCEDURE [IF NOT EXISTS] ...
+CREATE TABLE [IF NOT EXISTS] ...
+CREATE TRIGGER [IF NOT EXISTS] ...
+CREATE VIEW [IF NOT EXISTS] ...
+CREATE FILTER [IF NOT EXISTS] ...
+CREATE DOMAIN [IF NOT EXISTS] ...
+CREATE FUNCTION [IF NOT EXISTS] ...
+DECLARE EXTERNAL FUNCTION [IF NOT EXISTS] ...
+CREATE SHADOW [IF NOT EXISTS] ...
+CREATE ROLE [IF NOT EXISTS] ...
+CREATE GENERATOR [IF NOT EXISTS] ...
+CREATE SEQUENCE [IF NOT EXISTS] ...
+CREATE COLLATION [IF NOT EXISTS] ...
+CREATE USER [IF NOT EXISTS] ...
+CREATE PACKAGE [IF NOT EXISTS] ...
+CREATE PACKAGE BODY [IF NOT EXISTS] ...
+CREATE [GLOBAL] MAPPING [IF NOT EXISTS] ...
+ALTER TABLE <table> ADD [IF NOT EXISTS] <column name> ...
+ALTER TABLE <table> ADD CONSTRAINT [IF NOT EXISTS] <constraint name> ...

src/common/security.h

@@ -220,6 +220,7 @@ public:
 	unsigned int op;
 	int trustedAuth;
 	bool silent;
+	bool createIfNotExistsOnly = false;
 	CharField user, pass, first, last, middle, com, attr;
 	IntField adm, act;
 	CharField database, dba, dbaPassword, role;

src/dsql/DdlNodes.epp

@@ -1789,6 +1789,9 @@ void CreateAlterFunctionNode::executeCreate(thread_db* tdbb, DsqlCompilerScratch
 
 	if (package.isEmpty())
 	{
+		if (createIfNotExistsOnly && !DYN_UTIL_check_unique_name_nothrow(tdbb, transaction, name, obj_udf))
+			return;
+
 		executeDdlTrigger(tdbb, dsqlScratch, transaction, DTW_BEFORE,
 			DDL_TRIGGER_CREATE_FUNCTION, name, NULL);
 
@@ -2804,6 +2807,9 @@ void CreateAlterProcedureNode::executeCreate(thread_db* tdbb, DsqlCompilerScratc
 
 	if (package.isEmpty())
 	{
+		if (createIfNotExistsOnly && !DYN_UTIL_check_unique_name_nothrow(tdbb, transaction, name, obj_procedure))
+			return;
+
 		executeDdlTrigger(tdbb, dsqlScratch, transaction, DTW_BEFORE,
 			DDL_TRIGGER_CREATE_PROCEDURE, name, NULL);
 
@@ -3724,9 +3730,14 @@ void CreateAlterTriggerNode::execute(thread_db* tdbb, DsqlCompilerScratch* dsqlS
 void CreateAlterTriggerNode::executeCreate(thread_db* tdbb, DsqlCompilerScratch* dsqlScratch,
 	jrd_tra* transaction)
 {
+	if (createIfNotExistsOnly && !DYN_UTIL_check_unique_name_nothrow(tdbb, transaction, name, obj_trigger))
+		return;
+
 	executeDdlTrigger(tdbb, dsqlScratch, transaction, DTW_BEFORE, DDL_TRIGGER_CREATE_TRIGGER,
 		name, NULL);
 
+	DYN_UTIL_check_unique_name(tdbb, transaction, name, obj_trigger);
+
 	store(tdbb, dsqlScratch, transaction);
 
 	executeDdlTrigger(tdbb, dsqlScratch, transaction, DTW_AFTER, DDL_TRIGGER_CREATE_TRIGGER,
@@ -4010,9 +4021,14 @@ void CreateCollationNode::execute(thread_db* tdbb, DsqlCompilerScratch* dsqlScra
 	// run all statements under savepoint control
 	AutoSavePoint savePoint(tdbb, transaction);
 
+	if (createIfNotExistsOnly && !DYN_UTIL_check_unique_name_nothrow(tdbb, transaction, name, obj_collation))
+		return;
+
 	executeDdlTrigger(tdbb, dsqlScratch, transaction, DTW_BEFORE,
 		DDL_TRIGGER_CREATE_COLLATION, name, NULL);
 
+	DYN_UTIL_check_unique_name(tdbb, transaction, name, obj_collation);
+
 	AutoCacheRequest request(tdbb, drq_s_colls, DYN_REQUESTS);
 
 	STORE(REQUEST_HANDLE request TRANSACTION_HANDLE transaction)
@@ -4400,9 +4416,14 @@ void CreateDomainNode::execute(thread_db* tdbb, DsqlCompilerScratch* dsqlScratch
 	// run all statements under savepoint control
 	AutoSavePoint savePoint(tdbb, transaction);
 
+	if (createIfNotExistsOnly && !DYN_UTIL_check_unique_name_nothrow(tdbb, transaction, nameType->name, obj_field))
+		return;
+
 	executeDdlTrigger(tdbb, dsqlScratch, transaction, DTW_BEFORE,
 		DDL_TRIGGER_CREATE_DOMAIN, nameType->name, NULL);
 
+	DYN_UTIL_check_unique_name(tdbb, transaction, nameType->name, obj_field);
+
 	storeGlobalField(tdbb, transaction, nameType->name, type);
 
 	if (nameType->defaultClause || check || notNull)
@@ -5539,6 +5560,9 @@ void CreateAlterExceptionNode::executeCreate(thread_db* tdbb, DsqlCompilerScratc
 	Attachment* const attachment = transaction->getAttachment();
 	const MetaString& ownerName = attachment->getEffectiveUserName();
 
+	if (createIfNotExistsOnly && !DYN_UTIL_check_unique_name_nothrow(tdbb, transaction, name, obj_exception))
+		return;
+
 	executeDdlTrigger(tdbb, dsqlScratch, transaction, DTW_BEFORE,
 		DDL_TRIGGER_CREATE_EXCEPTION, name, NULL);
 
@@ -5766,9 +5790,14 @@ void CreateAlterSequenceNode::putErrorPrefix(Firebird::Arg::StatusVector& status
 void CreateAlterSequenceNode::executeCreate(thread_db* tdbb, DsqlCompilerScratch* dsqlScratch,
 	jrd_tra* transaction)
 {
+	if (createIfNotExistsOnly && !DYN_UTIL_check_unique_name_nothrow(tdbb, transaction, name, obj_generator))
+		return;
+
 	executeDdlTrigger(tdbb, dsqlScratch, transaction, DTW_BEFORE, DDL_TRIGGER_CREATE_SEQUENCE,
 		name, NULL);
 
+	DYN_UTIL_check_unique_name(tdbb, transaction, name, obj_generator);
+
 	const SINT64 val = value.value_or(1);
 	SLONG initialStep = 1;
 	if (step.has_value())
@@ -5777,6 +5806,7 @@ void CreateAlterSequenceNode::executeCreate(thread_db* tdbb, DsqlCompilerScratch
 		if (initialStep == 0)
 			status_exception::raise(Arg::Gds(isc_dyn_cant_use_zero_increment) << Arg::Str(name));
 	}
+
 	store(tdbb, transaction, name, fb_sysflag_user, val, initialStep);
 
 	executeDdlTrigger(tdbb, dsqlScratch, transaction, DTW_AFTER, DDL_TRIGGER_CREATE_SEQUENCE,
@@ -6398,11 +6428,25 @@ void RelationNode::defineField(thread_db* tdbb, DsqlCompilerScratch* dsqlScratch
 	const ObjectsArray<MetaName>* pkCols)
 {
 	dsql_fld* field = clause->field;
+	dsql_rel* relation = dsqlScratch->relation;
+
+	if (clause->createIfNotExistsOnly)
+	{
+		AutoCacheRequest request(tdbb, drq_l_rel_fld_name, DYN_REQUESTS);
+
+		FOR(REQUEST_HANDLE request TRANSACTION_HANDLE transaction)
+			RFL IN RDB$RELATION_FIELDS
+			WITH RFL.RDB$RELATION_NAME = relation->rel_name.c_str() AND
+				 RFL.RDB$FIELD_NAME = field->fld_name.c_str()
+		{
+			return;
+		}
+		END_FOR
+	}
 
 	// Add the field to the relation being defined for parsing purposes.
 
 	bool permanent = false;
-	dsql_rel* relation = dsqlScratch->relation;
 	if (relation != NULL)
 	{
 		if (!(relation->rel_flags & REL_new_relation))
@@ -6596,12 +6640,26 @@ bool RelationNode::defineDefault(thread_db* /*tdbb*/, DsqlCompilerScratch* dsqlS
 }
 
 // Make a constraint object from a legacy node.
-void RelationNode::makeConstraint(thread_db* /*tdbb*/, DsqlCompilerScratch* dsqlScratch,
+void RelationNode::makeConstraint(thread_db* tdbb, DsqlCompilerScratch* dsqlScratch,
 	jrd_tra* transaction, AddConstraintClause* clause,
 	ObjectsArray<CreateDropConstraint>& constraints, bool* notNull)
 {
 	MemoryPool& pool = dsqlScratch->getPool();
 
+	if (clause->createIfNotExistsOnly)
+	{
+		AutoCacheRequest request(tdbb, drq_l_rel_con, DYN_REQUESTS);
+
+		FOR(REQUEST_HANDLE request TRANSACTION_HANDLE transaction)
+			RC IN RDB$RELATION_CONSTRAINTS
+			WITH RC.RDB$CONSTRAINT_NAME EQ clause->name.c_str() AND
+				 RC.RDB$RELATION_NAME EQ name.c_str()
+		{
+			return;
+		}
+		END_FOR
+	}
+
 	switch (clause->constraintType)
 	{
 		case AddConstraintClause::CTYPE_NOT_NULL:
@@ -7474,6 +7532,9 @@ void CreateRelationNode::checkPermission(thread_db* tdbb, jrd_tra* transaction)
 void CreateRelationNode::execute(thread_db* tdbb, DsqlCompilerScratch* dsqlScratch,
 	jrd_tra* transaction)
 {
+	if (createIfNotExistsOnly && !DYN_UTIL_check_unique_name_nothrow(tdbb, transaction, name, obj_relation))
+		return;
+
 	saveRelation(tdbb, dsqlScratch, name, false, true);
 
 	if (externalFile)
@@ -8790,6 +8851,9 @@ void CreateAlterViewNode::checkPermission(thread_db* tdbb, jrd_tra* transaction)
 void CreateAlterViewNode::execute(thread_db* tdbb, DsqlCompilerScratch* dsqlScratch,
 	jrd_tra* transaction)
 {
+	if (createIfNotExistsOnly && !DYN_UTIL_check_unique_name_nothrow(tdbb, transaction, name, obj_relation))
+		return;
+
 	Attachment* const attachment = transaction->tra_attachment;
 	const MetaString& ownerName = attachment->getEffectiveUserName();
 
@@ -9962,6 +10026,9 @@ void CreateIndexNode::execute(thread_db* tdbb, DsqlCompilerScratch* dsqlScratch,
 	// run all statements under savepoint control
 	AutoSavePoint savePoint(tdbb, transaction);
 
+	if (createIfNotExistsOnly && !DYN_UTIL_check_unique_name_nothrow(tdbb, transaction, name, obj_index))
+		return;
+
 	executeDdlTrigger(tdbb, dsqlScratch, transaction, DTW_BEFORE, DDL_TRIGGER_CREATE_INDEX,
 		name, NULL);
 
@@ -10402,6 +10469,9 @@ void CreateShadowNode::execute(thread_db* tdbb, DsqlCompilerScratch* /*dsqlScrat
 		FIRST 1 X IN RDB$FILES
 		WITH X.RDB$SHADOW_NUMBER EQ number
 	{
+		if (createIfNotExistsOnly)
+			return;
+
 		// msg 165: "Shadow %ld already exists"
 		status_exception::raise(Arg::PrivateDyn(165) << Arg::Num(number));
 	}
@@ -10522,6 +10592,10 @@ void CreateAlterRoleNode::execute(thread_db* tdbb, DsqlCompilerScratch* dsqlScra
 
 	// run all statements under savepoint control
 	AutoSavePoint savePoint(tdbb, transaction);
+	MetaName dummyName;
+
+	if (createIfNotExistsOnly && isItSqlRole(tdbb, transaction, name, dummyName))
+		return;
 
 	executeDdlTrigger(tdbb, dsqlScratch, transaction, DTW_BEFORE,
 		createFlag ? DDL_TRIGGER_CREATE_ROLE : DDL_TRIGGER_ALTER_ROLE, name, NULL);
@@ -10544,7 +10618,6 @@ void CreateAlterRoleNode::execute(thread_db* tdbb, DsqlCompilerScratch* dsqlScra
 		status_exception::raise(Arg::PrivateDyn(193) << name);
 	}
 
-	MetaName dummyName;
 	if (createFlag && isItSqlRole(tdbb, transaction, name, dummyName))
 	{
 		// msg 194: "SQL role @1 already exists"
@@ -10701,6 +10774,8 @@ void MappingNode::runInSecurityDb(SecDbContext* secDbContext)
 	{
 	case MAP_ADD:
 		ddl = "CREATE MAPPING ";
+		if (createIfNotExistsOnly)
+			ddl += "IF NOT EXISTS ";
 		break;
 	case MAP_MOD:
 		ddl = "ALTER MAPPING ";
@@ -11014,6 +11089,8 @@ void MappingNode::execute(thread_db* tdbb, DsqlCompilerScratch* dsqlScratch, jrd
 	case MAP_ADD:
 		if (found)
 		{
+			if (createIfNotExistsOnly)
+				return;
 			(Arg::Gds(isc_map_already_exists) << name).raise();
 		}
 		// fall through ...
@@ -11261,6 +11338,8 @@ void CreateAlterUserNode::execute(thread_db* tdbb, DsqlCompilerScratch* dsqlScra
 			(Arg::Gds(isc_random) << "Missing user name for ALTER CURRENT USER").raise();
 	}
 
+	userData->createIfNotExistsOnly = createIfNotExistsOnly;
+
 	Firebird::LocalStatus s;
 	CheckStatusWrapper statusWrapper(&s);
 

src/dsql/DdlNodes.h

@@ -475,6 +475,7 @@ public:
 	MetaName name;
 	bool create;
 	bool alter;
+	bool createIfNotExistsOnly = false;
 	NestConst<ExternalClause> external;
 	Firebird::TriState deterministic;
 	Firebird::Array<NestConst<ParameterClause> > parameters;
@@ -614,6 +615,7 @@ public:
 	MetaName name;
 	bool create;
 	bool alter;
+	bool createIfNotExistsOnly = false;
 	NestConst<ExternalClause> external;
 	Firebird::Array<NestConst<ParameterClause> > parameters;
 	Firebird::Array<NestConst<ParameterClause> > returns;
@@ -789,6 +791,7 @@ private:
 public:
 	bool create;
 	bool alter;
+	bool createIfNotExistsOnly = false;
 	NestConst<LocalDeclarationsNode> localDeclList;
 	NestConst<StmtNode> body;
 	bool compiled;
@@ -888,6 +891,7 @@ public:
 	MetaName fromName;
 	Firebird::string fromExternal;
 	Firebird::UCharBuffer specificAttributes;
+	bool createIfNotExistsOnly = false;
 
 private:
 	USHORT attributesOn;
@@ -949,6 +953,7 @@ public:
 	NestConst<ParameterClause> nameType;
 	bool notNull;
 	NestConst<BoolSourceClause> check;
+	bool createIfNotExistsOnly = false;
 };
 
 
@@ -1068,6 +1073,7 @@ public:
 	Firebird::string message;
 	bool create;
 	bool alter;
+	bool createIfNotExistsOnly = false;
 };
 
 
@@ -1152,6 +1158,7 @@ private:
 public:
 	bool create;
 	bool alter;
+	bool createIfNotExistsOnly = false;
 	bool legacy;
 	bool restartSpecified;
 	const MetaName name;
@@ -1380,6 +1387,7 @@ public:
 		Firebird::ObjectsArray<MetaName> refColumns;
 		NestConst<RefActionClause> refAction;
 		NestConst<BoolSourceClause> check;
+		bool createIfNotExistsOnly = false;
 	};
 
 	struct IdentityOptions
@@ -1422,6 +1430,7 @@ public:
 		NestConst<ValueSourceClause> computed;
 		NestConst<IdentityOptions> identityOptions;
 		bool notNullSpecified;
+		bool createIfNotExistsOnly = false;
 	};
 
 	struct AlterColNameClause : public Clause
@@ -1596,6 +1605,7 @@ public:
 	std::optional<rel_t> relationType = rel_persistent;
 	bool preserveRowsOpt;
 	bool deleteRowsOpt;
+	bool createIfNotExistsOnly = false;
 };
 
 
@@ -1699,6 +1709,7 @@ private:
 public:
 	bool create;
 	bool alter;
+	bool createIfNotExistsOnly = false;
 	NestConst<ValueListNode> viewFields;
 	NestConst<SelectExprNode> selectExpr;
 	Firebird::string source;
@@ -1783,6 +1794,7 @@ public:
 	NestConst<ValueListNode> columns;
 	NestConst<ValueSourceClause> computed;
 	NestConst<BoolSourceClause> partial;
+	bool createIfNotExistsOnly = false;
 };
 
 
@@ -1990,6 +2002,7 @@ public:
 	bool manual;
 	bool conditional;
 	Firebird::Array<NestConst<DbFileClause> > files;
+	bool createIfNotExistsOnly = false;
 };
 
 
@@ -2067,7 +2080,9 @@ private:
 
 public:
 	MetaName name;
-	bool createFlag, sysPrivDrop;
+	bool createFlag;
+	bool sysPrivDrop;
+	bool createIfNotExistsOnly = false;
 
 	void addPrivilege(const MetaName* privName)
 	{
@@ -2127,6 +2142,7 @@ public:
 	bool global = false;
 	bool role = false;
 	bool silentDrop = false;
+	bool createIfNotExistsOnly = false;
 };
 
 
@@ -2226,6 +2242,7 @@ public:
 	Firebird::TriState adminRole;
 	Firebird::TriState active;
 	Mode mode;
+	bool createIfNotExistsOnly = false;
 
 	void addProperty(MetaName* pr, Firebird::string* val = NULL)
 	{

src/dsql/PackageNodes.epp

@@ -27,6 +27,7 @@
 #include "../jrd/jrd.h"
 #include "../jrd/tra.h"
 #include "../jrd/dfw_proto.h"
+#include "../jrd/dyn_ut_proto.h"
 #include "../jrd/exe_proto.h"
 #include "../jrd/met_proto.h"
 #include "../jrd/vio_proto.h"
@@ -363,9 +364,14 @@ void CreateAlterPackageNode::executeCreate(thread_db* tdbb, DsqlCompilerScratch*
 	Attachment* const attachment = transaction->getAttachment();
 	const MetaString& ownerName = attachment->getEffectiveUserName();
 
+	if (createIfNotExistsOnly && !DYN_UTIL_check_unique_name_nothrow(tdbb, transaction, name, obj_package_header))
+		return;
+
 	executeDdlTrigger(tdbb, dsqlScratch, transaction, DTW_BEFORE,
 		DDL_TRIGGER_CREATE_PACKAGE, name, NULL);
 
+	DYN_UTIL_check_unique_name(tdbb, transaction, name, obj_package_header);
+
 	AutoCacheRequest requestHandle(tdbb, drq_s_pkg, DYN_REQUESTS);
 
 	STORE (REQUEST_HANDLE requestHandle TRANSACTION_HANDLE transaction)
@@ -789,6 +795,9 @@ void CreatePackageBodyNode::execute(thread_db* tdbb, DsqlCompilerScratch* dsqlSc
 	{
 		if (!PKG.RDB$VALID_BODY_FLAG.NULL && PKG.RDB$VALID_BODY_FLAG != 0)
 		{
+			if (createIfNotExistsOnly)
+				return;
+
 			status_exception::raise(
 				Arg::Gds(isc_no_meta_update) <<
 				Arg::Gds(isc_dyn_package_body_exists) << Arg::Str(name));

src/dsql/PackageNodes.h

@@ -107,6 +107,7 @@ public:
 	MetaName name;
 	bool create;
 	bool alter;
+	bool createIfNotExistsOnly = false;
 	Firebird::string source;
 	Firebird::Array<Item>* items;
 	Firebird::SortedArray<MetaName> functionNames;
@@ -179,6 +180,7 @@ public:
 	Firebird::string source;
 	Firebird::Array<CreateAlterPackageNode::Item>* declaredItems;
 	Firebird::Array<CreateAlterPackageNode::Item>* items;
+	bool createIfNotExistsOnly = false;
 
 private:
 	Firebird::string owner;

src/dsql/parse-conflicts.txt

@@ -1 +1 @@
-94 shift/reduce conflicts, 22 reduce/reduce conflicts.
+115 shift/reduce conflicts, 22 reduce/reduce conflicts.

src/dsql/parse.y

@@ -822,6 +822,7 @@ using namespace Firebird;
 	Jrd::ValueSourceClause* valueSourceClause;
 	Jrd::RelationNode* relationNode;
 	Jrd::RelationNode::AddColumnClause* addColumnClause;
+	Jrd::RelationNode::AddConstraintClause* addConstraintClause;
 	Jrd::RelationNode::RefActionClause* refActionClause;
 	Jrd::RelationNode::IndexConstraintClause* indexConstraintClause;
 	Jrd::RelationNode::IdentityOptions* identityOptions;
@@ -1406,7 +1407,12 @@ declare
 %type <ddlNode> declare_clause
 declare_clause
 	: FILTER filter_decl_clause				{ $$ = $2; }
-	| EXTERNAL FUNCTION udf_decl_clause		{ $$ = $3; }
+	| EXTERNAL FUNCTION if_not_exists_opt udf_decl_clause
+		{
+			const auto node = $4;
+			node->createIfNotExistsOnly = $3;
+			$$ = node;
+		}
 	;
 
 %type <createAlterFunctionNode> udf_decl_clause
@@ -1534,37 +1540,129 @@ create
 
 %type <ddlNode> create_clause
 create_clause
-	: EXCEPTION exception_clause				{ $$ = $2; }
+	: EXCEPTION if_not_exists_opt exception_clause
-	| unique_opt order_direction INDEX symbol_index_name ON simple_table_name
+		{
+			const auto node = $3;
+			node->createIfNotExistsOnly = $2;
+			$$ = node;
+		}
+	| unique_opt order_direction INDEX if_not_exists_opt symbol_index_name ON simple_table_name
 			{
-				CreateIndexNode* node = newNode<CreateIndexNode>(*$4);
+				const auto node = newNode<CreateIndexNode>(*$5);
 				node->unique = $1;
 				node->descending = $2;
-				node->relation = $6;
+				node->createIfNotExistsOnly = $4;
+				node->relation = $7;
 				$$ = node;
 			}
-		index_definition(static_cast<CreateIndexNode*>($7))
+		index_definition(static_cast<CreateIndexNode*>($8))
 			{
-				$$ = $7;
+				$$ = $8;
 			}
-	| FUNCTION function_clause					{ $$ = $2; }
+	| FUNCTION if_not_exists_opt function_clause
-	| PROCEDURE procedure_clause				{ $$ = $2; }
+		{
-	| TABLE table_clause						{ $$ = $2; }
+			const auto node = $3;
-	| GLOBAL TEMPORARY TABLE gtt_table_clause	{ $$ = $4; }
+			node->createIfNotExistsOnly = $2;
-	| TRIGGER trigger_clause					{ $$ = $2; }
+			$$ = node;
-	| VIEW view_clause							{ $$ = $2; }
+		}
-	| GENERATOR generator_clause				{ $$ = $2; }
+	| PROCEDURE if_not_exists_opt procedure_clause
-	| SEQUENCE generator_clause					{ $$ = $2; }
+		{
+			const auto node = $3;
+			node->createIfNotExistsOnly = $2;
+			$$ = node;
+		}
+	| TABLE if_not_exists_opt table_clause
+		{
+			const auto node = $3;
+			node->createIfNotExistsOnly = $2;
+			$$ = node;
+		}
+	| GLOBAL TEMPORARY TABLE if_not_exists_opt gtt_table_clause
+		{
+			const auto node = $5;
+			node->createIfNotExistsOnly = $4;
+			$$ = node;
+		}
+	| TRIGGER if_not_exists_opt trigger_clause
+		{
+			const auto node = $3;
+			node->createIfNotExistsOnly = $2;
+			$$ = node;
+		}
+	| VIEW if_not_exists_opt view_clause
+		{
+			const auto node = $3;
+			node->createIfNotExistsOnly = $2;
+			$$ = node;
+		}
+	| GENERATOR if_not_exists_opt generator_clause
+		{
+			const auto node = $3;
+			node->createIfNotExistsOnly = $2;
+			$$ = node;
+		}
+	| SEQUENCE if_not_exists_opt generator_clause
+		{
+			const auto node = $3;
+			node->createIfNotExistsOnly = $2;
+			$$ = node;
+		}
 	| DATABASE db_clause						{ $$ = $2; }
-	| DOMAIN domain_clause						{ $$ = $2; }
+	| DOMAIN if_not_exists_opt domain_clause
-	| SHADOW shadow_clause						{ $$ = $2; }
+		{
-	| ROLE role_clause							{ $2->createFlag = true; $$ = $2; }
+			const auto node = $3;
-	| COLLATION collation_clause				{ $$ = $2; }
+			node->createIfNotExistsOnly = $2;
-	| USER create_user_clause					{ $$ = $2; }
+			$$ = node;
-	| PACKAGE package_clause					{ $$ = $2; }
+		}
-	| PACKAGE BODY package_body_clause			{ $$ = $3; }
+	| SHADOW if_not_exists_opt shadow_clause
-	| MAPPING create_map_clause(false)			{ $$ = $2; }
+		{
-	| GLOBAL MAPPING create_map_clause(true)	{ $$ = $3; }
+			const auto node = $3;
+			node->createIfNotExistsOnly = $2;
+			$$ = node;
+		}
+	| ROLE if_not_exists_opt role_clause
+		{
+			const auto node = $3;
+			node->createIfNotExistsOnly = $2;
+			node->createFlag = true;
+			$$ = node;
+		}
+	| COLLATION if_not_exists_opt collation_clause
+		{
+			const auto node = $3;
+			node->createIfNotExistsOnly = $2;
+			$$ = node;
+		}
+	| USER if_not_exists_opt create_user_clause
+		{
+			const auto node = $3;
+			node->createIfNotExistsOnly = $2;
+			$$ = node;
+		}
+	| PACKAGE if_not_exists_opt package_clause
+		{
+			const auto node = $3;
+			node->createIfNotExistsOnly = $2;
+			$$ = node;
+		}
+	| PACKAGE BODY if_not_exists_opt package_body_clause
+		{
+			const auto node = $4;
+			node->createIfNotExistsOnly = $3;
+			$$ = node;
+		}
+	| MAPPING if_not_exists_opt create_map_clause(false)
+		{
+			const auto node = $3;
+			node->createIfNotExistsOnly = $2;
+			$$ = node;
+		}
+	| GLOBAL MAPPING if_not_exists_opt create_map_clause(true)
+		{
+			const auto node = $4;
+			node->createIfNotExistsOnly = $3;
+			$$ = node;
+		}
 	;
 
 
@@ -2345,7 +2443,7 @@ table_element($createRelationNode)
 
 // column definition
 
-%type column_def(<relationNode>)
+%type <addColumnClause> column_def(<relationNode>)
 column_def($relationNode)
 	: symbol_column_name data_type_or_domain domain_default_opt
 			{
@@ -2359,6 +2457,7 @@ column_def($relationNode)
 		column_constraint_clause(NOTRIAL($<addColumnClause>4)) collate_clause
 			{
 				setCollate($2, $6);
+				$$ = $<addColumnClause>4;
 			}
 	| symbol_column_name data_type_or_domain identity_clause
 			{
@@ -2372,6 +2471,7 @@ column_def($relationNode)
 		column_constraint_clause(NOTRIAL($<addColumnClause>4)) collate_clause
 			{
 				setCollate($2, $6);
+				$$ = $<addColumnClause>4;
 			}
 	| symbol_column_name non_array_type def_computed
 		{
@@ -2381,6 +2481,7 @@ column_def($relationNode)
 			clause->computed = $3;
 			$relationNode->clauses.add(clause);
 			clause->field->flags |= FLD_computed;
+			$$ = clause;
 		}
 	| symbol_column_name def_computed
 		{
@@ -2390,6 +2491,7 @@ column_def($relationNode)
 			clause->computed = $2;
 			$relationNode->clauses.add(clause);
 			clause->field->flags |= FLD_computed;
+			$$ = clause;
 		}
 	;
 
@@ -2577,15 +2679,13 @@ column_constraint($addColumnClause)
 
 // table constraints
 
-%type table_constraint_definition(<relationNode>)
+%type <addConstraintClause> table_constraint_definition(<relationNode>)
 table_constraint_definition($relationNode)
 	: constraint_name_opt table_constraint($relationNode)
 		{
 			if ($1)
-			{
+				$2->name = *$1;
-				static_cast<RelationNode::AddConstraintClause*>(
+			$$ = $2;
-					$relationNode->clauses.back().getObject())->name = *$1;
-			}
 		}
 	;
 
@@ -2595,7 +2695,7 @@ constraint_name_opt
 	| CONSTRAINT symbol_constraint_name		{ $$ = $2; }
 	;
 
-%type table_constraint(<relationNode>)
+%type <addConstraintClause> table_constraint(<relationNode>)
 table_constraint($relationNode)
 	: UNIQUE column_parens constraint_index_opt
 		{
@@ -2611,6 +2711,7 @@ table_constraint($relationNode)
 			constraint.index = $3;
 
 			$relationNode->clauses.add(&constraint);
+			$$ = &constraint;
 		}
 	| PRIMARY KEY column_parens constraint_index_opt
 		{
@@ -2626,6 +2727,7 @@ table_constraint($relationNode)
 			constraint.index = $4;
 
 			$relationNode->clauses.add(&constraint);
+			$$ = &constraint;
 		}
 	| FOREIGN KEY column_parens REFERENCES symbol_table_name column_parens_opt
 		referential_trigger_action constraint_index_opt
@@ -2654,6 +2756,7 @@ table_constraint($relationNode)
 			constraint.index = $8;
 
 			$relationNode->clauses.add(&constraint);
+			$$ = &constraint;
 		}
 	| check_constraint
 		{
@@ -2661,6 +2764,7 @@ table_constraint($relationNode)
 			constraint->constraintType = RelationNode::AddConstraintClause::CTYPE_CHECK;
 			constraint->check = $1;
 			$relationNode->clauses.add(constraint);
+			$$ = constraint;
 		}
 	;
 
@@ -4267,8 +4371,18 @@ alter_op($relationNode)
 			clause->name = *$4;
 			$relationNode->clauses.add(clause);
 		}
-	| ADD column_def($relationNode)
+	| ADD if_not_exists_opt column_def($relationNode)
-	| ADD table_constraint_definition($relationNode)
+		{
+			const auto node = $3;
+			node->createIfNotExistsOnly = $2;
+		}
+	| ADD table_constraint($relationNode)
+	| ADD CONSTRAINT if_not_exists_opt symbol_constraint_name table_constraint($relationNode)
+		{
+			const auto node = $5;
+			node->name = *$4;
+			node->createIfNotExistsOnly = $3;
+		}
 	| col_opt alter_column_name POSITION pos_short_integer
 		{
 			RelationNode::AlterColPosClause* clause = newNode<RelationNode::AlterColPosClause>();
@@ -4917,6 +5031,12 @@ if_exists_opt
 	| IF EXISTS			{ $$ = true; }
 	;
 
+%type <boolVal> if_not_exists_opt
+if_not_exists_opt
+	: /* nothing */		{ $$ = false; }
+	| IF NOT EXISTS		{ $$ = true; }
+	;
+
 %type <boolVal> opt_no_file_delete
 opt_no_file_delete
 	: /* nothing */			{ $$ = false; }

src/include/firebird/impl/msg/dyn.h

@@ -299,3 +299,7 @@ FB_IMPL_MSG(DYN, 306, dyn_rel_not_exist, -901, "42", "000", "Table @1 does not e
 FB_IMPL_MSG(DYN, 307, dyn_exc_not_exist, -901, "42", "000", "Exception @1 does not exist")
 FB_IMPL_MSG(DYN, 308, dyn_gen_not_exist, -901, "42", "000", "Generator/Sequence @1 does not exist")
 FB_IMPL_MSG(DYN, 309, dyn_fld_not_exist, -901, "42", "000", "Field @1 of table @2 does not exist")
+FB_IMPL_MSG_SYMBOL(DYN, 310, dyn_dup_trigger, "Trigger @1 already exists")
+FB_IMPL_MSG_SYMBOL(DYN, 311, dyn_dup_domain, "Domain @1 already exists")
+FB_IMPL_MSG_SYMBOL(DYN, 312, dyn_dup_collation, "Collation @1 already exists")
+FB_IMPL_MSG_SYMBOL(DYN, 313, dyn_dup_package, "Package @1 already exists")

src/jrd/UserManagement.cpp

@@ -482,8 +482,13 @@ void UserManagement::execute(USHORT id)
 	}
 
 	int errcode = manager->execute(&statusWrapper, command, NULL);
-	if (!command->silent)
+
+	if (!command->silent &&
+		!(command->createIfNotExistsOnly &&
+			fb_utils::containsErrorCode(status.getErrors(), isc_unique_key_violation)))
+	{
 		checkSecurityResult(errcode, &status, command->userName()->get(), command->operation());
+	}
 
 	delete commands[id];
 	commands[id] = NULL;

src/jrd/drq.h

@@ -249,6 +249,12 @@ enum drq_type_t
 	drq_l_pub_rel_name,		// lookup relation by name
 	drq_l_pub_all_rels,		// iterate through all user relations
 	drq_e_pub_tab_all,		// erase relation from all publication
+	drq_l_trg_name,			// lookup trigger name
+	drq_l_fld_name,			// lookup field name
+	drq_l_coll_name,		// lookup collation name
+	drq_l_pkg_name,			// lookup package name
+	drq_l_rel_con,			// lookup relation constraint
+	drq_l_rel_fld_name,		// lookup relation field name
 
 	drq_MAX
 };

src/jrd/dyn_ut_proto.h

@@ -37,6 +37,8 @@ void	DYN_UTIL_generate_field_position(Jrd::thread_db*, const Jrd::MetaName&, SLO
 void	DYN_UTIL_generate_field_name(Jrd::thread_db*, TEXT*);
 void	DYN_UTIL_generate_field_name(Jrd::thread_db*, Jrd::MetaName&);
 void	DYN_UTIL_generate_constraint_name(Jrd::thread_db*, Jrd::MetaName&);
+bool DYN_UTIL_check_unique_name_nothrow(Jrd::thread_db* tdbb, Jrd::jrd_tra* transaction,
+	const Jrd::MetaName& object_name, int object_type, USHORT* errorCode = nullptr);
 void	DYN_UTIL_check_unique_name(Jrd::thread_db* tdbb, Jrd::jrd_tra* transaction,
 								   const Jrd::MetaName& object_name, int object_type);
 SINT64	DYN_UTIL_gen_unique_id(Jrd::thread_db*, SSHORT, const char*);

src/jrd/dyn_util.epp

@@ -78,23 +78,16 @@ static const UCHAR gen_id_blr2[] =
 		blr_parameter, 0, 0, 0, blr_end, blr_end, blr_end, blr_eoc
 };
 
-void DYN_UTIL_check_unique_name(thread_db* tdbb, jrd_tra* transaction,
+// Check if an object already exists. If yes, return false.
-	const MetaName& object_name, int object_type)
+bool DYN_UTIL_check_unique_name_nothrow(thread_db* tdbb, jrd_tra* transaction,
+	const MetaName& object_name, int object_type, USHORT* errorCode)
 {
-/**************************************
- *
- *	D Y N _ U T I L _ c h e c k _ u n i q u e _ n a m e
- *
- **************************************
- *
- * Functional description
- *	Check if an object already exists.
- *	If yes then return error.
- *
- **************************************/
 	SET_TDBB(tdbb);
 
-	USHORT error_code = 0;
+	USHORT tempErrorCode;
+	errorCode = errorCode ? errorCode : &tempErrorCode;
+	*errorCode = 0;
+
 	AutoCacheRequest request;
 
 	switch (object_type)
@@ -106,11 +99,11 @@ void DYN_UTIL_check_unique_name(thread_db* tdbb, jrd_tra* transaction,
 			FOR(REQUEST_HANDLE request TRANSACTION_HANDLE transaction)
 				EREL IN RDB$RELATIONS WITH EREL.RDB$RELATION_NAME EQ object_name.c_str()
 			{
-				error_code = 132;
+				*errorCode = 132;
 			}
 			END_FOR
 
-			if (!error_code)
+			if (!*errorCode)
 			{
 				request.reset(tdbb, drq_l_prc_name, DYN_REQUESTS);
 
@@ -119,7 +112,7 @@ void DYN_UTIL_check_unique_name(thread_db* tdbb, jrd_tra* transaction,
 					WITH EPRC.RDB$PROCEDURE_NAME EQ object_name.c_str() AND
 						 EPRC.RDB$PACKAGE_NAME MISSING
 				{
-					error_code = 135;
+					*errorCode = 135;
 				}
 				END_FOR
 			}
@@ -131,7 +124,7 @@ void DYN_UTIL_check_unique_name(thread_db* tdbb, jrd_tra* transaction,
 			FOR(REQUEST_HANDLE request TRANSACTION_HANDLE transaction)
 				EIDX IN RDB$INDICES WITH EIDX.RDB$INDEX_NAME EQ object_name.c_str()
 			{
-				error_code = 251;
+				*errorCode = 251;
 			}
 			END_FOR
 
@@ -143,7 +136,7 @@ void DYN_UTIL_check_unique_name(thread_db* tdbb, jrd_tra* transaction,
 			FOR(REQUEST_HANDLE request TRANSACTION_HANDLE transaction)
 				EXCP IN RDB$EXCEPTIONS WITH EXCP.RDB$EXCEPTION_NAME EQ object_name.c_str()
 			{
-				error_code = 253;
+				*errorCode = 253;
 			}
 			END_FOR
 
@@ -155,7 +148,7 @@ void DYN_UTIL_check_unique_name(thread_db* tdbb, jrd_tra* transaction,
 			FOR(REQUEST_HANDLE request TRANSACTION_HANDLE transaction)
 				EGEN IN RDB$GENERATORS WITH EGEN.RDB$GENERATOR_NAME EQ object_name.c_str()
 			{
-				error_code = 254;
+				*errorCode = 254;
 			}
 			END_FOR
 
@@ -169,7 +162,59 @@ void DYN_UTIL_check_unique_name(thread_db* tdbb, jrd_tra* transaction,
 				WITH EFUN.RDB$FUNCTION_NAME EQ object_name.c_str() AND
 					 EFUN.RDB$PACKAGE_NAME MISSING
 			{
-				error_code = 268;
+				*errorCode = 268;
+			}
+			END_FOR
+
+			break;
+
+		case obj_trigger:
+			request.reset(tdbb, drq_l_trg_name, DYN_REQUESTS);
+
+			FOR(REQUEST_HANDLE request TRANSACTION_HANDLE transaction)
+				TRG IN RDB$TRIGGERS
+				WITH TRG.RDB$TRIGGER_NAME EQ object_name.c_str()
+			{
+				*errorCode = 310;
+			}
+			END_FOR
+
+			break;
+
+		case obj_field:
+			request.reset(tdbb, drq_l_fld_name, DYN_REQUESTS);
+
+			FOR(REQUEST_HANDLE request TRANSACTION_HANDLE transaction)
+				FLD IN RDB$FIELDS
+				WITH FLD.RDB$FIELD_NAME EQ object_name.c_str()
+			{
+				*errorCode = 311;
+			}
+			END_FOR
+
+			break;
+
+		case obj_collation:
+			request.reset(tdbb, drq_l_coll_name, DYN_REQUESTS);
+
+			FOR(REQUEST_HANDLE request TRANSACTION_HANDLE transaction)
+				COLL IN RDB$COLLATIONS
+				WITH COLL.RDB$COLLATION_NAME EQ object_name.c_str()
+			{
+				*errorCode = 312;
+			}
+			END_FOR
+
+			break;
+
+		case obj_package_header:
+			request.reset(tdbb, drq_l_pkg_name, DYN_REQUESTS);
+
+			FOR(REQUEST_HANDLE request TRANSACTION_HANDLE transaction)
+				PKG IN RDB$PACKAGES
+				WITH PKG.RDB$PACKAGE_NAME EQ object_name.c_str()
+			{
+				*errorCode = 313;
 			}
 			END_FOR
 
@@ -179,8 +224,16 @@ void DYN_UTIL_check_unique_name(thread_db* tdbb, jrd_tra* transaction,
 			fb_assert(false);
 	}
 
-	if (error_code)
+	return *errorCode == 0;
-		status_exception::raise(Arg::PrivateDyn(error_code) << object_name.c_str());
+}
+
+// Check if an object already exists. If yes, throw error.
+void DYN_UTIL_check_unique_name(thread_db* tdbb, jrd_tra* transaction, const MetaName& object_name, int object_type)
+{
+	USHORT errorCode;
+
+	if (!DYN_UTIL_check_unique_name_nothrow(tdbb, transaction, object_name, object_type, &errorCode))
+		status_exception::raise(Arg::PrivateDyn(errorCode) << object_name.c_str());
 }