Implementing Server-side Integration

On previous steps we've done good job.

Now it's time to learn how to work with data stored in the database and how should we treat CRUD (create, read, update, delete) operations so that they not only appear on the page, but also change data in the database.

The tasks for server-side are as follows:

  • To populate our list with data from the database;
  • To ensure that all the changes you make on the client side (within the component) should be reflected in the database (items should be added, deleted and updated in the DB)

Server side Integration is described in detail in the related article of documentation while here let's make the following steps:

Loading Data from the Database

Data loading is performed with the help of DataConnector, a script that retrieves data from the necessary database table and renders its data to the component. With library package, you get a wide choice of data connectors to serve the needs of server-side work. There exist .Net, PHP and Java versions.

The connector should be set as data url for a component.

    view: "list", id: "mylist",
    template: "#title# - #year#",
    select: true,
    url: "../common/connector.php",
    datatype: "xml"

Data Connector enables only server->client interaction, it's the component's data source. Used alone, it doesn't push client-side changes back to the database, which is the responsibility of DataProcessor.

DataProcessor Initialization

Webix.DataProcessor is responsible for server-side integration and handles all the CRUD operations.

It should be initialized for the component you'd like to perform server work with:

var dp = new webix.DataProcessor({
    master: $$('mylist'),  // specifies the desired component
    url: "../common/connector.php"  // specifies the server API endpoint

Very often DataProcessor gets the same url that is specified as component data source. At the same time, it can be your own piece of code if you want your own custom logic.

DataProcessor will automatically "translate" all your actions to the server: when you add a record to the list, the new record will appear in the database table, etc.

Component Binding

At last, let's make a step up and simplify form update. On the previous step we used an "onAfterSelect" event to transmit list data into the form and a complicated "update_row" function to push edited data back to list. It was for the sake of learning.

At the same time, Webix library has powerful Binding API to enable data synchronization between components. Bind() function is used to make one component a data source for another one on selection basis.

The update(); function is no longer needed as well since from now on we apply save(); method to the form to push changes back to the list and the database.

    view: "toolbar",
    cols: [
            view: "button",
            id: "update",
            value: "Save",
            width: 100,
            click: "$$('myform').save()"
    ]  // the new function for the button
$$("myform").bind($$("mylist")); //component binding

Addition and removal of items goes the same way as it was on previous step.

Related sample:  Creating Basic App. Step 3

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