Demapio

Small SQL mapper for C#

What?

It's like Dapper, but smaller and more focussed.

Why not just use Dapper?

If that works, do it. I keep having trouble with new versions of Dapper being 'smart' and re-writing my working SQL into broken SQL.

Demapio does a lot less, and aims to be small and stable rather than big and clever. No guarantees on speed.

Demapio deliberately uses unusual names for its extension methods, so it can be easily used alongside Dapper.

How?

Select a single value:

var conn = new NpgsqlConnection(ConnStr);

object? result = conn.QueryValue("SELECT ('Hello, ' || :para) as result;", new { para = "world" });

Query data to a list of C# objects:

var conn = new NpgsqlConnection(ConnStr);

var result = conn.SelectType<SamplePoco>("SELECT * FROM TestTable WHERE userId=:userId", new {userId = 10}).ToList()!;

Query data to a list of dynamic C# objects:

var conn = new NpgsqlConnection(ConnStr);

var result = conn.SelectDynamic("SELECT id, myValue FROM TestTable WHERE userId=:userId", new {userId = 10}).ToList()!;
Console.WriteLine(result.id, result.myValue);

Repeat a single statement with a batch of parameters:

var conn = new NpgsqlConnection(ConnStr);

conn.RepeatCommand("INSERT INTO TestTable (id, userId, deviceId) VALUES (:id, :userId, :deviceId);",
    new {id=1, userId=10, deviceId="User10 Phone"},
    new {id=2, userId=10, deviceId="User10 PC"},
    new {id=3, userId=20, deviceId="User20 Phone"},
    new {id=4, userId=20, deviceId="User20 Modem"}
);

Execute a statement, returning rows changed:

var conn = new NpgsqlConnection(ConnStr);

var changeCount = conn.CountCommand("UPDATE TestTable SET userId = :userId, deviceId = :deviceId WHERE id = :id;", new {id=1, userId=10, deviceId="User10 Phone"});
if (changeCount < 1) ...

Query data to an IDataReader:

var conn = new NpgsqlConnection(ConnStr);

using var result = conn.QueryReader("SELECT * FROM TestTable WHERE userId=:userId", new {userId = 10});
while (result.Read()) { ...