- Dapper Tutorial - Part 1: Dapper Intro and Installation
- Dapper Tutorial - Part 2: Dapper Queries
- Dapper Tutorial - Part 3: Simple CRUD
Intro to Dapper
Dapper is simple object mapper written in .NET and titled by many Number 1 Micro ORM. In terms of speed it is almost as fast as raw ADO.NET data reader. Basically Dapper extends IDbConnection object and provides additional methods and interfaces for querying data.
How Dapper works
- Instantiate IDbConnection object
- Write query or call stored procedure
- Pass the query and the parameters to one of the methods that Dapper provide
Install Dapper
Easiest way to install Dapper is through NuGet. The command to install the package is Install-Package Dapper, but you can also install it from NuGet Package Explorer
Database Requirements
Dapper will work across all .NET ADO provider including:
- SQLite
- SQL CE
- Firebird
- Oracle
- MySQL
- PostgreSQL
- SQL Server
Dapper methods
New methods that Dapper brings to IDbConnection interface:
- Execute: Executes command one or many times and return number of affected rows.
- Query: Execute query or stored procedure and maps the result.
- QueryFirst: Execute query or stored procedure and maps the first result. Throws exception if nothing found.
- QueryFirstOrDefault: Execute query or stored procedure and maps the first result. If nothing found return default.
- QuerySingle: Execute query or stored procedure and maps the first result. Throws exception if there are more results or none.
- QuerySingleOrDefault: Execute query or stored procedure and maps the first result. Throws exception if there are more results.
- QueryMultiple: Execute multiple queries and map results.
Parameters for Dapper methods
- Anonymous: new {Id = itemId, Type = importType}
- Dynamic
- List: new {IdList = new[]{item1Id, item2Id, item3Id} }
- String: new {Id = new DbString {Id = “item1Id”, IsFixedLength = false, Length = 6, IsAnsi = true}}
What Dapper methods return?
- Anonymous
- Strongly Typed
- Multi-Mapping
- Multi-Result
- Multi-Type
Dapper speed
Performance of SELECT mapping over 500 iterations - POCO serialization
| Method | Duration |
|---|---|
| SqlDataReader | 47ms |
| Dapper | 49ms |
| ServiceStack.OrmLite | 50ms |
| PetaPoco | 52ms |
| BLToolkit | 80ms |
| NHibernate SQL | 104ms |
| SubSonic Coding Horror | 107ms |
| Linq 2 SQL | 181ms |
| Entity Framework | 631ms |
Performance of SELECT mapping over 500 iterations - dynamic serialization
| Method | Duration |
|---|---|
| Dapper | 48ms |
| Massive | 52ms |
| Simple.Data | 95ms |
Performance of SELECT mapping over 500 iterations - typical usage
| Method | Duration |
|---|---|
| Linq 2 SQL CompiledQuery | 81ms |
| NHibernate HQL | 118ms |
| Linq 2 SQL | 559ms |
| Entity Framework | 859ms |
| SubSonic ActiveRecord.SingleOrDefault | 3619ms |
The performance benchmarks are available here.