var db=null;

​

function createDatabase() {

  if (!window.indexedDB) {

    window.alert("Your browser doesn't support a stable version of IndexedDB. Such and such feature will not be available.");

}

// This is what our customer data looks like.

var customerData = [

  { ssn: "444-44-4444", name: "Bill", age: 35, email: "bill@company.com" },

  { ssn: "555-55-5555", name: "Donna", age: 32, email: "donna@home.org" }

];

var dbName = "CustomerDB";

// Open database with version=2. Use integer valueonly ! Not 1.1, 1.2 etc.

var request = indexedDB.open(dbName, 2);

request.onerror = function(event) {

  // Handle errors.

  console.log("request.onerror errcode=" + event.target.error.name);

};

request.onupgradeneeded = function(event) {

  console.log("request.onupgradeneeded, we are creating a new version of the dataBase");

  db = event.target.result;

  // Create an objectStore to hold information about our customers. We're

  // going to use "ssn" as our key path because it's guaranteed to be

  // unique.

  var objectStore = db.createObjectStore("customers", { keyPath: "ssn" });

  // Create an index to search customers by name. We may have duplicates

  // so we can't use a unique index.

  objectStore.createIndex("name", "name", { unique: false });

  // Create an index to search customers by email. We want to ensure that

  // no two customers have the same email, so use a unique index.

  objectStore.createIndex("email", "email", { unique: true });

  // Store values in the newly created objectStore.

  for (var i in customerData) {

    objectStore.add(customerData[i]);

  }

};

  request.onsuccess = function(event) {

  console.log("request.onsuccess, database opened, now we can add / remove / look for data in it!");

    // The result is the database itself

  db = event.target.result;  

  };

   }

  function addACustomer() {

    if(db === null) {

      alert('Database must be opened first, please click the Create CustomerDB Database first');

      return;

    }

    var transaction = db.transaction(["customers"], "readwrite");

    // Do something when all the data is added to the database.

    transaction.oncomplete = function(event) {

        console.log("All done!");

    };

    transaction.onerror = function(event) {

       console.log("transaction.onerror" + event.target.errorCode);

    };

    var objectStore = transaction.objectStore("customers");

    var newCustomer={};

    newCustomer.ssn = document.querySelector("#ssn").value;

    newCustomer.name = document.querySelector("#name").value;

    newCustomer.age = document.querySelector("#age").value;

    newCustomer.email = document.querySelector("#email").value;

    alert('adding customer ssn=' + newCustomer.ssn);

    var request = objectStore.add(newCustomer);

    request.onsuccess = function(event) {

     console.log("Customer with ssn= " + event.target.result + " added.");

    };

     request.onerror = function(event) {

     alert("request.onerror, could not insert customer, errcode = " + event.target.error.name + ". Certainly either the ssn or the email is already present in the Database");

    };

​

}

​

 function removeACustomer() {

    if(db === null) {

      alert('Database must be opened first, please click the Create CustomerDB Database first');

      return;

    }

    var transaction = db.transaction(["customers"], "readwrite");

    // Do something when all the data is added to the database.

    transaction.oncomplete = function(event) {

        console.log("All done!");

    };

    transaction.onerror = function(event) {

       console.log("transaction.onerror errcode=" + event.target.error.name);

    };

    var objectStore = transaction.objectStore("customers");

    alert('removing customer ssn=444-44-4444');

    var request = objectStore.delete("444-44-4444");

    request.onsuccess = function(event) {

     console.log("Customer removed.");

    };

​

     request.onerror = function(event) {

     alert("request.onerror, could not remove customer, errcode = " + event.target.error.name + ". The ssn does not exist in the Database");

    };

​

}