DynamicOData

This library converts OData filter queries into IQueryable objects that encapsulate a query against a remote database, without requiring compiled C# classes.

The query generator requires an initial schema expressed as an IDictionary<string, Type> where each key value pair represents the name and type of a column in the database table.

Installation

Install-Package DynamicOData

Usage

The DynamicOData.QueryHost object encapsulates functionality.

public QueryHost(string tableName, Dictionary<string, Type> columns, string connectionStringOrName)

QueryHost exposes a single function:

public IQueryable GetQuery(string odata)

Example

var host = new QueryHost("TodoItem", new Dictionary<string, Type>
    {
        { "id", typeof (String) },
        { "text", typeof (String) },
        { "createdAt", typeof (DateTimeOffset) },
        { "updatedAt", typeof (DateTimeOffset) },
        { "deleted", typeof (bool) },
        { "version", typeof (Byte[]) }
    }, "connectionStringOrName");

List<object> todoItems = await host
	.GetQuery("createdAt gt datetime'2017-01-01T00:00:00.000Z' and deleted eq false")
	.ToListAsync();

How Does it Work?

DynamicOData generates and compiles a C# POCO and Entity Framework DbContext class from the supplied metadata and uses this to generate an IQueryable against any data source supported by Entity Framework.

It also generates an EdmModel class that is used to parse supplied OData queries. These filters are applied to IQueryable objects generated by Entity Framework and returned.

Creation of QueryHost objects is an expensive operation and instances should be reused wherever possible.