Tutorials

Building dynamic queries with EasyQuery and Entity Framework

Here we describe how EasyQuery helps to implement a query building UI for creating custom, dynamic queries in .NET projects which use Entity Framework (6.x)

Dynamic PHP query builder with EasyQuery

Dynamic PHP query builder with EasyQuery

Previous versions' tutorials (obsolete)

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

Dynamic queries for ASP.NET Core projects with Entity Framework Core

It takes a few minutes to add a new page with all necessary UI for building dynamic queries and to setup a middleware that will process all requests from that page, convert those request to the queries to your DB and return the result set back for visualization. This step is necessary to get the trial keys for EasyQuery framework. One for ASP.NET Core packages and another one - for EasyQuery.JS scripts. To simplify this task EasyQuery includes a Razor UI library package ( Korzh.EasyQuery.RazorUI ) that contains several predefined pages which you can use in your projects. For example, there is an "advaced search" page which is available via /EasyQuery/AdvancedSearch .

Entity class

Represents one entity

Entity class

Represents one entity

Entity class

Represents one entity

Entities page

This page describes entities participating in the data model and their attributes.

Dynamically populate lists by information from other conditions — WebForms

A code snippet which demonstrates how to execute this task

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

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.

Building data model dynamically by information from a DataTable

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

Query with OR operators

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

Query with a subquery

How to build queries with subqueries using EasyQuery.

Dynamically populate value lists by information from other conditions

Suppose we have a database with Customer entity which has Country and City attributes. For both these attributes we define the value editors which return the lists of available values (countries and cities correspondingly). Now let's imagine the user adds a condition with the Country attribute e.g. Hera the steps needed to implement such a functionality: Define a value editor for the City attribute as SQL LIST with Cities.@{{Customer.Country}} list name (here Customer.Country is the ID of the Country attribute in the Customer entity). Let's name it "CitesSqlValueList") and then in a value list resolver modify its SQL according the currently selected country and get the list of values using GetValueListAsync method of EasyQueryManager class: What's happening here.

Create a query with sub-query by code

Example with code

Hide some entities and/or attributes

Here we explain how to implement different ways to limit the quantity of entities and attributes shown in Data Model

Common SQL queries

Dynamic populating of value lists in WinForms or WPF editions

Example of how to solve this problem