of not exitsts fields

packages/datalib/src/ChangeSet.ts

@@ -20,6 +20,7 @@ export interface ChangeSetItem {
   document?: any;
   condition?: { [column: string]: string };
   fields?: { [column: string]: string };
+  insertIfNotExistsFields?: { [column: string]: string };
 }
 
 export interface ChangeSetItemFields {
@@ -284,6 +285,9 @@ function changeSetInsertToSql(
       targetTable,
       commandType: 'insert',
       fields,
+      insertWhereNotExistsCondition: item.insertIfNotExistsFields
+        ? compileSimpleChangeSetCondition(item.insertIfNotExistsFields)
+        : null,
     },
     autoInc
       ? {
@@ -332,6 +336,36 @@ export function extractChangeSetCondition(item: ChangeSetItem, alias?: string):
   };
 }
 
+function compileSimpleChangeSetCondition(fields: { [column: string]: string }): Condition {
+  function getColumnCondition(columnName: string): Condition {
+    const value = fields[columnName];
+    const expr: Expression = {
+      exprType: 'column',
+      columnName,
+    };
+    if (value == null) {
+      return {
+        conditionType: 'isNull',
+        expr,
+      };
+    } else {
+      return {
+        conditionType: 'binary',
+        operator: '=',
+        left: expr,
+        right: {
+          exprType: 'value',
+          value,
+        },
+      };
+    }
+  }
+  return {
+    conditionType: 'and',
+    conditions: _.keys(fields).map(columnName => getColumnCondition(columnName)),
+  };
+}
+
 function changeSetUpdateToSql(item: ChangeSetItem, dbinfo: DatabaseInfo = null): Update {
   const table = dbinfo?.tables?.find(x => x.schemaName == item.schemaName && x.pureName == item.pureName);
 

packages/sqltree/src/dumpSqlCommand.ts

@@ -92,13 +92,28 @@ export function dumpSqlDelete(dmp: SqlDumper, cmd: Delete) {
 }
 
 export function dumpSqlInsert(dmp: SqlDumper, cmd: Insert) {
-  dmp.put(
-    '^insert ^into %f (%,i) ^values (',
-    cmd.targetTable,
-    cmd.fields.map(x => x.targetColumn)
-  );
-  dmp.putCollection(',', cmd.fields, x => dumpSqlExpression(dmp, x));
-  dmp.put(')');
+  if (cmd.insertWhereNotExistsCondition) {
+    dmp.put(
+      '^insert ^into %f (%,i) ^select ',
+      cmd.targetTable,
+      cmd.fields.map(x => x.targetColumn)
+    );
+    dmp.putCollection(',', cmd.fields, x => dumpSqlExpression(dmp, x));
+    if (dmp.dialect.requireFromDual) {
+      dmp.put(' ^from ^dual ');
+    }
+    dmp.put(' ^where ^not ^exists (^select * ^from %f ^where ', cmd.targetTable);
+    dumpSqlCondition(dmp, cmd.insertWhereNotExistsCondition);
+    dmp.put(')');
+  } else {
+    dmp.put(
+      '^insert ^into %f (%,i) ^values (',
+      cmd.targetTable,
+      cmd.fields.map(x => x.targetColumn)
+    );
+    dmp.putCollection(',', cmd.fields, x => dumpSqlExpression(dmp, x));
+    dmp.put(')');
+  }
 }
 
 export function dumpSqlCommand(dmp: SqlDumper, cmd: Command) {

packages/sqltree/src/types.ts

@@ -38,6 +38,7 @@ export interface Insert {
   commandType: 'insert';
   fields: UpdateField[];
   targetTable: NamedObjectInfo;
+  insertWhereNotExistsCondition?: Condition;
 }
 
 export interface AllowIdentityInsert {

packages/types/dialect.d.ts

@@ -34,6 +34,7 @@ export interface SqlDialect {
   dropCheck?: boolean;
 
   dropReferencesWhenDropTable?: boolean;
+  requireFromDual?: boolean;
 
   predefinedDataTypes: string[];
 

plugins/dbgate-plugin-oracle/src/frontend/drivers.js

@@ -35,6 +35,7 @@ const dialect = {
   dropCheck: true,
 
   dropReferencesWhenDropTable: true,
+  requireFromDual: true,
 
   predefinedDataTypes: [
     'VARCHAR2',