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:

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.

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.

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

Building data model dynamically by information from a DataTable

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

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.

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

Working with data models in EasyQuery

This article will guide you through all issues about working with data models in EasyQuery library. How to load it from the DbContext or from your DB connection, or now to create a new one using Data Model Editor.

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

Here you can find all steps you need to perform

Create virtual (calculated) attribute in you model

Virtual attributes: what are they for and how to add one

Attaching extra data to a query on the client-side

Sometimes it's necessary to attach some extra data to each query (based on some user's input on the client-side) and then use that extra data on query execution. For example, user might want to specify a date (or a period of time) as an additional filter to the any query. To add some extra data you can use beforeExecuteQuery event handler which can be defined on view initialization: Now if you check in Developer Tools (on Network tab), each .../execute request now includes ad additional data object in the request payload. Now to process this additional request data you can create your own implementation of EasyQueryManager and override its ExecuteQueryCore method. Here is an example: Here we just reconfigure our current query and add in it an additional condition group with a bunch of conditions like SomeColumns contains 'filter text' Finally, you need to register your manager class on EasyQuery middleware initialization: NB: Please note that you can read the ClientData property in any method of your custom manager.

Managing data formats

This article shows how to implement some particular tasks with your query

DataModel class

Represents a data model

DataModel class

Represents a data model

MetaData class

Read-only constant that represent the latest format version of data model definition JSON files

DataModel class

Represents a data model