ExecuteReader

This method executes a raw SQL statement directly against the database and returns a DbDataReader object. It supports all RDBMS data providers.

Code Snippets

The following example reads all rows from the [dbo].[Person] table.

using (var connection = new SqlConnection(connectionString))
{
    using (var reader = connection.ExecuteReader("SELECT * FROM [dbo].[Person];"))
    {
        // Process the reader here
    }
}

Passing of Parameters

Parameters can be passed via any of the following types:

IDbDataParameter
Anonymous Types
ExpandoObject
Dictionary<string, object>
QueryField/QueryGroup

IDbDataParameter

using (var connection = new SqlConnection(connectionString))
{
    using (var reader = connection.ExecuteReader("SELECT * FROM [dbo].[Person] WHERE Id = @Id;", new { Id = new SqlParameter("_", 10045) }))
    {
        // Process the reader here
    }
}

The parameter name is not required. The library replaces it with the actual property name from the object.

Anonymous Types

using (var connection = new SqlConnection(connectionString))
{
    using (var reader = connection.ExecuteReader("SELECT * FROM [dbo].[Person] WHERE Id = @Id;", new { Id = 10045 }))
    {
        // Process the reader here
    }
}

ExpandoObject

using (var connection = new SqlConnection(connectionString))
{
    var param = new ExpandoObject() as IDictionary<string, object>;
    param.Add("Id", 10045);
    using (var reader = connection.ExecuteReader("SELECT * FROM [dbo].[Person] WHERE Id = @Id;", param))
    {
        // Process the reader here
    }
}

Dictionary<string, object>

using (var connection = new SqlConnection(connectionString))
{
    var param = new Dictionary<string, object>
    {
        { "Id", 10045 }
    };
    using (var reader = connection.ExecuteReader("SELECT * FROM [dbo].[Person] WHERE Id = @Id;", param))
    {
        // Process the reader here
    }
}

QueryField/QueryGroup

using (var connection = new SqlConnection(connectionString))
{
    var param = new []
    {
        new QueryField("Id", 10045)
    };
    using (var reader = connection.ExecuteReader("SELECT * FROM [dbo].[Person] WHERE Id = @Id;", param))
    {
        // Process the reader here
    }
}

Or via QueryGroup.

using (var connection = new SqlConnection(connectionString))
{
    var param = new QueryGroup(new []
    {
        new QueryField("Id", 10045)
    });
    using (var reader = connection.ExecuteReader("SELECT * FROM [dbo].[Person] WHERE Id = @Id;", param))
    {
        // Process the reader here
    }
}

Array Parameters (for the IN keyword)

Pass an array of values when using the IN keyword.

using (var connection = new SqlConnection(connectionString))
{
    var param = new
    {
        Keys = new [] { 10045, 10102, 11004 }
    };
    using (var reader = connection.ExecuteReader("SELECT * FROM dbo].[Person] WHERE Id IN (@Keys);", param))
    {
        // Process the reader here
    }
}

Any of the parameter types listed in Passing of Parameters can also be used here.

Executing a Stored Procedure

There are two ways to execute a stored procedure. Pass the stored procedure name and set the command type to CommandType.StoredProcedure:

using (var connection = new SqlConnection(connectionString))
{
    using (var reader = connection.ExecuteReader("[dbo].[sp_GetPerson]", new { Id = 10045 }, commandType: CommandType.StoredProcedure))
    {
        // Process the reader here
    }
}

Or use a native SQL EXEC call:

using (var connection = new SqlConnection(connectionString))
{
    using (var reader = connection.ExecuteReader("EXEC [dbo].[sp_GetPerson](@Id);", new { Id = 10045 }))
    {
        // Process the reader here
    }
}

In the second call, the command text ends with a semicolon and no command type is set.