Tutorials

Data Model Editor

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:

Previous versions' tutorials (obsolete)

This section contains the tutorials that we written for older versions of EasyQuery and most probably are obsolete now.

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

Value Editors

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

Operator class

Represents a logical expression or predicate, like comparisions or LIKE predicate.

Operator class

Represents a logical expression or "predicate". For example: "less than", "is equal to", "starts with".

Operator class

Represents a logical expression or "predicate". For example: "less than", "is equal to", "starts with".

Query with OR operators

In this article, you will learn how to build queries that contain both AND and OR operators.

Operators page

This article defines operators which can be used in conditions (such as 'is equal to', 'less than' and others).

Add a new aggregate function

EasyQuery allows to add new aggregate functions for user's need. Here is detailed manual of how to do it with code example.

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)..

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.

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.

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 information from a DataTable

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

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