graphql: create history table before running

Jobs/GraphQL/GraphQLJob.vb

@@ -120,7 +120,11 @@ Public Class GraphQLJob
             ' Clear Table before inserting
             If pQuery.ClearBeforeFill = True Then
                 If DeleteWithQueryName(pQuery) = False Then
-                    Throw New ApplicationException($"Error while clearing table before fill for Query [{pQuery.Name}]")
+                    Throw New ApplicationException($"Error while dropping history table before fill for Query [{pQuery.Name}]")
+                End If
+
+                If CreateHistoryTable(pQuery) = False Then
+                    Throw New ApplicationException($"Error while creating history table before fill for Query [{pQuery.Name}]")
                 End If
             End If
 
@@ -196,12 +200,28 @@ Public Class GraphQLJob
         End Try
     End Function
 
-    Private Function DeleteWithQueryName(pQuery)
+    Private Function DeleteWithQueryName(pQuery As GraphQL.Query) As Boolean
-        Dim oDeleteSQL = $"TRUNCATE TABLE {pQuery.DestinationTable}"
+        Dim oHistoryTableName = $"{pQuery.DestinationTable}_HISTORY"
-        Return _MSSQL.ExecuteNonQuery(oDeleteSQL)
+        Dim oDeleteHistorySQL = $"
+            IF (EXISTS (SELECT *
+            FROM INFORMATION_SCHEMA.TABLES
+            WHERE TABLE_SCHEMA = 'dbo'
+            AND TABLE_NAME = '{oHistoryTableName}'))
+            BEGIN
+            DROP TABLE {oHistoryTableName};
+            END"
+
+        Return _MSSQL.ExecuteNonQuery(oDeleteHistorySQL)
     End Function
 
-    Private Function DeleteWithStatus(pQuery As Query, pStatus As Integer)
+    Private Function CreateHistoryTable(pQuery As Query) As Boolean
+        Dim oHistoryTableName = $"{pQuery.DestinationTable}_HISTORY"
+        Dim oFillHistorySQL = $"SELECT * INTO {oHistoryTableName} FROM {pQuery.DestinationTable}"
+
+        Return _MSSQL.ExecuteNonQuery(oFillHistorySQL)
+    End Function
+
+    Private Function DeleteWithStatus(pQuery As Query, pStatus As Integer) As Boolean
         Dim oDeleteSQL = $"DELETE FROM {pQuery.DestinationTable} WHERE STATUS = {pStatus} AND ADDED_QUERY_ID = '{pQuery.Id}'"
         Return _MSSQL.ExecuteNonQuery(oDeleteSQL)
     End Function