Improve view bypass lab before and after flow

scenarios/04-view-bypass-mac/sql/00_schema.sql

@@ -1,14 +1,28 @@
 WHENEVER SQLERROR EXIT SQL.SQLCODE
 
-CREATE TABLE dds_mac_accounts (
-  account_id   NUMBER PRIMARY KEY,
-  account_name VARCHAR2(100),
-  owner_name   VARCHAR2(60),
-  region       VARCHAR2(30),
-  balance      NUMBER(12,2)
-);
-
-CREATE VIEW dds_mac_accounts_view AS
-SELECT account_id, account_name, owner_name, region, balance
-FROM dds_mac_accounts;
+BEGIN
+  EXECUTE IMMEDIATE q'[
+    CREATE TABLE dds_mac_accounts (
+      account_id   NUMBER PRIMARY KEY,
+      account_name VARCHAR2(100),
+      owner_name   VARCHAR2(60),
+      region       VARCHAR2(30),
+      balance      NUMBER(12,2)
+    )
+  ]';
+EXCEPTION
+  WHEN OTHERS THEN
+    IF SQLCODE != -955 THEN
+      RAISE;
+    END IF;
+END;
+/
 
+BEGIN
+  EXECUTE IMMEDIATE q'[
+    CREATE OR REPLACE VIEW dds_mac_accounts_view AS
+    SELECT account_id, account_name, owner_name, region, balance
+    FROM dds_mac_accounts
+  ]';
+END;
+/