Data Model Editor

From a sample to your own project

[EasyQuery GitHub repositories](https://github.com/easyquery) contain several sample projects that demonstrate how to use EasyQuery library on different platforms, with differen frameworks and in different scenarios. The best way to start with EasyQuery is to choose the sample closest to your scenario and modify it according to your requirements (your DB, data model, environment, layout, styles, etc). So, in this section we are going to describe how to do it.

About Data Model Editor

Here you can find detailed information about this instrument and guideline, how to use it to perform all needed tasks.

Data Model

In short (and by its name), data model - is a model (representation) of some data stored in your database. It solves two major problems: Presents the data to the end user in a more friendly and familiar way. Contains some meta information that helps EasyQuery components to build query statements in SQL or other query languages. Any data model contains the following main sections:

Value Editors

Here you can find the full list of editors and choose any you need in your work with Data Model:

Copying the EasyQuery's code from a sample to your project

If you have already modified one of our sample projects to make it work with your DB, the next step will be to copy the EasyQuery's code to your own solution. This article describes how to do it.

Creating data model dynamically with code

-Data Model- object is an essential part of EasyQuery framework. However, sometimes you need to add some entities, entity attributes or operators to the existing model or to fill it from scratch using DB metadata information got from another source. In these cases, you can use EasyQuery API to build the model dynamically. Finally, we add entities and entity attributes. Here is an example of creatin a small data model: two tables (Customers and Orders) with one link between them, 2 entities (Customer and Order correpondingly) and a few attributes in each entity.

Using EqMvcDemoEF sample with your own DB context

This article contains a brief instruction how to modify EqMvcDemoEF sample project to make it work with your own context class

Aggregate data

From this article you will see how to aggregate (count, sum, etc.) data in your queries.

Working with several data models

All EasyQuery demos works with one data model (and one database which corresponds to that model). Here we are going to describe how to add a selector that switches between two data models on your view/page and then how to setup a custom "model loader" to handle GetModel requests propertly. To make it possible to switch between these two models we need some selector element on our page. The only problem here - is to switch the database connection accordingly the the switches between the models. Now when the user selects an item in our model selector element on the client-side - our server-side code automatically loads the selected model and connects to a proper database (when necessary)..

Adding columns and conditions with code

Example of code for adding columns and conditions

Possible ways of data model creation and loading

EasyQuery components need a [data model](/$aid/03bc06b0-83ec-4040-97ef-a50ca004177f) (a user-friendly representation of your DB) for their work. There are several different ways to create the model and load it on your project's startup. This article will describe all of them in detail.

Building data model dynamically using code (version 3.x)

Here you can find all steps you need to perform

Navigate through data model entities and attributes

A code snippet which demonstrates how to run through data model entities and attributes

Building data model dynamically by DB meta-information

It's easier to fill your model right in the code directly from your database, using meta-information

Adding a new operator to your data model

Here you can find all information about how to add a new operator to your data model either using Data Model Editor (DME) or with a code

Building data model dynamically by information from a DataTable

Example of how to build data model by certain information from DataTable

Using MS SQL instead of Access in WebDemo sample project

In this article, you will find the detailed instructions how to modify WebDemoCS or WebDemoAjaxCS to make it work with SQL Server instead of Access

Introduction to value editors

For example, value editor allows you to define a list of available values - so your users will be able to select the value from a drop-down list. "Custom list" value editor raises an event which can be processed either on the client-side or on the server. All other editions of EasyQuery (WinForms, WebForms, WPF or Silverlight) has ListRequest event in QueryPanel control which is raised when a user adds an attribute (or operator) with Custom List or SQL list value editor assigned to that attribute/operator. Here we show how you can filter the returned list according to the value specified for some other attribute. If such condition is defined - we get the value (country code) from it and use that value as a filter for the list of regions.

Build query by code on the client-side

Here you can find an example of JavaScript code with explanation how to add columns to a current query on client-side.