Use async waterfall to avoid nesting. Fix comment

Author: cjbj

examples/insert1.js

@@ -1,4 +1,4 @@
-/* Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved. */
+/* Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved. */
 
 /******************************************************************************
  *
@@ -23,69 +23,117 @@
  *
  *****************************************************************************/
 
+var async = require('async');
 var oracledb = require('oracledb');
 var dbConfig = require('./dbconfig.js');
 
-oracledb.getConnection(
-  {
-    user          : dbConfig.user,
-    password      : dbConfig.password,
-    connectString : dbConfig.connectString
-  },
-  function(err, connection)
-  {
-    if (err) {
+var doconnect = function(cb) {
+  oracledb.getConnection(
+    {
+      user          : dbConfig.user,
+      password      : dbConfig.password,
+      connectString : dbConfig.connectString
+    },
+    cb);
+};
+
+var dorelease = function(conn) {
+  conn.release(function (err) {
+    if (err)
       console.error(err.message);
-      return;
-    }
-    connection.execute(
-      "CREATE TABLE test (id NUMBER, name VARCHAR2(20))",
-      function(err)
-      {
-        if (err) {
-          console.error(err.message);
-          return;
-        }
-        console.log("Table created");
+  });
+};
 
-        connection.execute(
-          "INSERT INTO test VALUES (:id, :nm)",
-          [1, 'Chris'],  // Bind values
-          function(err, result)
-          {
-            if (err) { console.error(err.message); return; }
-            console.log("Rows inserted: " + result.rowsAffected);  // 1
+var dodrop = function (conn, cb) {
+  conn.execute(
+    "BEGIN "
+  + "  EXECUTE IMMEDIATE 'DROP TABLE test'; "
+  + "  EXCEPTION WHEN OTHERS THEN "
+  + "  IF SQLCODE <> -942 THEN "
+  + "    RAISE; "
+  + "  END IF; "
+  + "END;",
+    function(err, result)
+    {
+      if (err) {
+        return cb(err, conn);
+      } else {
+        console.log("Table dropped");
+        return cb(null, conn);
+      }
+    });
+};
+
+var docreate = function (conn, cb) {
+  conn.execute(
+    "CREATE TABLE test (id NUMBER, name VARCHAR2(20))",
+    function(err, result)
+    {
+      if (err) {
+        return cb(err, conn);
+      } else {
+        console.log("Table created");
+        return cb(null, conn);
+      }
+    });
+};
 
-            connection.execute(
-              "INSERT INTO test VALUES (:id, :nm)",
-              [2, 'Alison'],  // Bind values
-              function(err, result)
-              {
-                if (err) { console.error(err.message); return; }
-                console.log("Rows inserted: " + result.rowsAffected);  // 1
+var doinsert1 = function (conn, cb) {
+  conn.execute(
+    "INSERT INTO test VALUES (:id, :nm)",
+    [1, 'Chris'],  // Bind values
+    function(err, result)
+    {
+      if (err) {
+        return cb(err, conn);
+      } else {
+        console.log("Rows inserted: " + result.rowsAffected);  // 1
+        return cb(null, conn);
+      }
+    });
+};
 
-                connection.execute(
-                  "UPDATE test SET name = 'Bambi'",
-                  function(err, result)
-                  {
-                    if (err) { console.error(err.message); return; }
-                    console.log("Rows updated: " + result.rowsAffected); // 2
+var doinsert2 = function (conn, cb) {
+  conn.execute(
+    "INSERT INTO test VALUES (:id, :nm)",
+    [2, 'Alison'],  // Bind values
+    function(err, result)
+    {
+      if (err) {
+        return cb(err, conn);
+      } else {
+        console.log("Rows inserted: " + result.rowsAffected);  // 1
+        return cb(null, conn);
+      }
+    });
+};
 
-                    connection.execute(
-                      "DROP TABLE test",
-                      function(err)
-                      {
-                        if (err) { console.error(err.message); return; }
-                        console.log("Table dropped");
+var doupdate = function (conn, cb) {
+  conn.execute(
+    "UPDATE test SET name = 'Bambi'",
+    function(err, result)
+    {
+      if (err) {
+        return cb(err, conn);
+      } else {
+        console.log("Rows updated: " + result.rowsAffected); // 2
+        return cb(null, conn);
+      }
+    });
+};
 
-                        connection.release(
-                          function(err)
-                          {
-                            if (err) { console.error(err.message); return; }
-                          });
-                      });
-                  });
-              });
-          });
-      });
+async.waterfall(
+  [
+    doconnect,
+    dodrop,
+    docreate,
+    doinsert1,
+    doinsert2,
+    doupdate,
+    dodrop
+  ],
+  function (err, conn) {
+    if (err) { console.error("In waterfall error cb: ==>", err, "<=="); }
+    if (conn)
+      dorelease(conn);
   });