feat(api): oracledb - sequence based ai field for older version

- enable it by setting `useTriggerBasedAI` to true under knex connection config

packages/nocodb/src/lib/db/sql-client/lib/oracle/OracleClient.ts

@@ -1568,10 +1568,15 @@ class OracleClient extends KnexClient {
 
       this.emit(`Success : ${upQuery}`);
 
+      const triggerStatements = await this.afterTableCreate(args);
+
       /**************** return files *************** */
       result.data.object = {
-        upStatement: [{ sql: upQuery }],
+        upStatement: [{ sql: upQuery }, ...triggerStatements.upStatement],
-        downStatement,
+        downStatement: [
+          ...triggerStatements.downStatement,
+          { sql: downStatement },
+        ],
       };
     } catch (e) {
       log.ppe(e, _func);
@@ -1581,6 +1586,63 @@ class OracleClient extends KnexClient {
     return result;
   }
 
+  // https://chartio.com/resources/tutorials/how-to-define-an-auto-increment-primary-key-in-oracle/
+  // fallback for older version to auto generate auto incremented pk using sequence and trigger
+  async afterTableCreate(args) {
+    const result = { upStatement: [], downStatement: [] };
+    let upQuery = '';
+    let downQuery = '';
+
+    const pk = args.columns.find((c) => c.pk);
+    if (!pk || !this.useTriggerBasedAI) return result;
+
+    for (let i = 0; i < args.columns.length; i++) {
+      const column = args.columns[i];
+      if (column.ai) {
+        const triggerName = `nc_trigger_${args.table_name}_${column.column_name}_on_insert`;
+        const sequenceName = `nc_sequence_${args.table_name}_${column.column_name}`;
+
+        const sequenceCreateQuery = this.genQuery(`CREATE SEQUENCE ??.??`, [
+          this.schema,
+          sequenceName,
+        ]);
+        const triggerCreateQuery = this.genQuery(
+          `CREATE OR REPLACE TRIGGER ??.??
+            BEFORE INSERT ON ??.??
+            FOR EACH ROW
+          BEGIN
+            SELECT ??.nextval
+            INTO :new.??
+            FROM dual;
+          END;`,
+          [
+            this.schema,
+            triggerName,
+            this.schema,
+            args.table_name,
+            sequenceName,
+            column.column_name,
+          ]
+        );
+
+        upQuery +=
+          sequenceCreateQuery + this.querySeparator() + triggerCreateQuery;
+
+        await this.sqlClient.raw(sequenceCreateQuery);
+        await this.sqlClient.raw(triggerCreateQuery);
+
+        downQuery +=
+          this.querySeparator() +
+          this.genQuery(`DROP TRIGGER ??.??`, [this.schema, triggerName]) +
+          this.querySeparator() +
+          this.genQuery(`DROP SEQUENCE ??.??`, [this.schema, sequenceName]);
+      }
+    }
+    result.upStatement[0] = { sql: upQuery };
+    result.downStatement[0] = { sql: downQuery };
+    return result;
+  }
+
   /**
    *
    * @param {Object} - args
@@ -2034,9 +2096,11 @@ class OracleClient extends KnexClient {
         query += scale ? `,${scale}` : '';
         query += n.dtxp && n.dtxp !== ' ' ? ')' : '';
       }
-      // todo: `IDENTITY` is not supported in older version,
+
-      //        add a fallback with sequence or trigger
+      // https://chartio.com/resources/tutorials/how-to-define-an-auto-increment-primary-key-in-oracle/
-      if (n.ai) {
+      // `IDENTITY` is not supported in older version,
+      //        use trigger based ai a fallback with sequence or trigger
+      if (n.ai && !this.useTriggerBasedAI) {
         query += ' GENERATED BY DEFAULT ON NULL AS IDENTITY';
       } else {
         query += n.rqd ? ' NOT NULL' : ' NULL';
@@ -2091,6 +2155,18 @@ class OracleClient extends KnexClient {
 
     return query;
   }
+
+  get schema() {
+    return this.connectionConfig.connection?.user;
+  }
+
+  // trigger based auto increment column
+  get useTriggerBasedAI() {
+    return (
+      this.connectionConfig.useTriggerBasedAI ??
+      this.connectionConfig.connection?.useTriggerBasedAI
+    );
+  }
 }
 
 function getDefaultValue(n) {

packages/nocodb/src/lib/db/sql-data-mapper/lib/sql/functionMappings/oracle.ts

@@ -76,6 +76,21 @@ const pg = {
       )} + 7, 7) ${colAlias}`
     );
   },
+  // AND: (args: MapFnArgs) => {
+  //   return args.knex.raw(
+  //     `CASE WHEN ${commonFns.AND({
+  //       ...args,
+  //       colAlias: '',
+  //     })} THEN 1 ELSE 0 END${args.colAlias}`
+  //   );
+  // },
+  // OR: (args: MapFnArgs) => {
+  //   return args.knex.raw(
+  //     `CASE WHEN ${commonFns.OR({ ...args, colAlias: '' })} THEN 1 ELSE 0 END${
+  //       args.colAlias
+  //     }`
+  //   );
+  // },
 };
 
 export default pg;