add an option to clear out the target table prior to moving data

app/src/main/java/jrunner/jrunner.java

@@ -20,6 +20,7 @@ public class jrunner {
         String sq =  "";
         String dt =  "";
         Boolean trim = true;
+        Boolean clear = true;
         Integer r = 0;
         Integer t = 0;
         String sql = "";
@@ -38,7 +39,7 @@ public class jrunner {
         Timestamp tsStart = null;
         Timestamp tsEnd   = null;
 
-        msg = "jrunner version 0.40";
+        msg = "jrunner version 0.41";
         msg = msg + nl + "-scu       source jdbc url";
         msg = msg + nl + "-scn       source username";
         msg = msg + nl + "-scp       source passowrd";
@@ -48,6 +49,7 @@ public class jrunner {
         msg = msg + nl + "-sq        path to source query";
         msg = msg + nl + "-dt        fully qualified name of destination table";
         msg = msg + nl + "-t         trim text";
+        msg = msg + nl + "-c         clear target table";
         msg = msg + nl + "--help     info";
 
         //---------------------------------------parse args into variables-------------------------------------------------
@@ -99,6 +101,9 @@ public class jrunner {
                 case "-t":
                     trim = true;
                     break;
+                case "-c":
+                    clear = true;
+                    break;
                 case "-v":
                     System.out.println(msg);
                     return;
@@ -198,9 +203,24 @@ public class jrunner {
             e.printStackTrace();
             System.exit(0);
         }
+        //-------------------------clear the target table if requeted----------------------------------------------------
+        if (clear) {
+            System.out.println("------------clear target table----------------------------");
+            sql = "DELETE FROM " + dt;
+            try {
+                stmtd = dcon.createStatement();
+                System.out.println(" " + sql);
+                stmtd.executeUpdate(sql);
+            } catch (SQLException e) {
+                e.printStackTrace();
+                System.out.println(sql);
+                System.exit(0);
+            }
+        }
         System.out.println("------------row count-------------------------------------");
         //-------------------------------build & execute sql-------------------------------------------------------------
         try {
+            sql = "";
             while (rs.next()) {
                 r++;
                 t++;