Dapper.Contrib - a simple object mapper for .Net
========================================
[](https://ci.appveyor.com/project/StackExchange/dapper-contrib)
Release Notes
-------------
Located at [dapperlib.github.io/Dapper.Contrib](https://dapperlib.github.io/Dapper.Contrib/)
Packages
--------
MyGet Pre-release feed: https://www.myget.org/gallery/dapper
| Package | NuGet Stable | NuGet Pre-release | Downloads | MyGet |
| ------- | ------------ | ----------------- | --------- | ----- |
| [Dapper.Contrib](https://www.nuget.org/packages/Dapper.Contrib/) | [](https://www.nuget.org/packages/Dapper.Contrib/) | [](https://www.nuget.org/packages/Dapper.Contrib/) | [](https://www.nuget.org/packages/Dapper.Contrib/) | [](https://www.myget.org/feed/dapper/package/nuget/Dapper.Contrib) |
Features
--------
Dapper.Contrib contains a number of helper methods for inserting, getting,
updating and deleting records.
The full list of extension methods in Dapper.Contrib right now are:
```csharp
T Get(id);
IEnumerable GetAll();
int Insert(T obj);
int Insert(Enumerable list);
bool Update(T obj);
bool Update(Enumerable list);
bool Delete(T obj);
bool Delete(Enumerable list);
bool DeleteAll();
```
For these extensions to work, the entity in question _MUST_ have a
key property. Dapper will automatically use a property named "`id`"
(case-insensitive) as the key property, if one is present.
```csharp
public class Car
{
public int Id { get; set; } // Works by convention
public string Name { get; set; }
}
```
If the entity doesn't follow this convention, decorate
a specific property with a `[Key]` or `[ExplicitKey]` attribute.
```csharp
public class User
{
[Key]
int TheId { get; set; }
string Name { get; set; }
int Age { get; set; }
}
```
`[Key]` should be used for database-generated keys (e.g. autoincrement columns),
while `[ExplicitKey]` should be used for explicit keys generated in code.
`Get` methods
-------
Get one specific entity based on id
```csharp
var car = connection.Get(1);
```
or a list of all entities in the table.
```csharp
var cars = connection.GetAll();
```
`Insert` methods
-------
Insert one entity
```csharp
connection.Insert(new Car { Name = "Volvo" });
```
or a list of entities.
```csharp
connection.Insert(cars);
```
`Update` methods
-------
Update one specific entity
```csharp
connection.Update(new Car() { Id = 1, Name = "Saab" });
```
or update a list of entities.
```csharp
connection.Update(cars);
```
`Delete` methods
-------
Delete an entity by the specified `[Key]` property
```csharp
connection.Delete(new Car() { Id = 1 });
```
a list of entities
```csharp
connection.Delete(cars);
```
or _ALL_ entities in the table.
```csharp
connection.DeleteAll();
```
Special Attributes
----------
Dapper.Contrib makes use of some optional attributes:
* `[Table("Tablename")]` - use another table name instead of the (by default pluralized) name of the class
```csharp
[Table ("emps")]
public class Employee
{
public int Id { get; set; }
public string Name { get; set; }
}
```
* `[Key]` - this property represents a database-generated identity/key
```csharp
public class Employee
{
[Key]
public int EmployeeId { get; set; }
public string Name { get; set; }
}
```
* `[ExplicitKey]` - this property represents an explicit identity/key which is
*not* automatically generated by the database
```csharp
public class Employee
{
[ExplicitKey]
public Guid EmployeeId { get; set; }
public string Name { get; set; }
}
```
* `[Write(true/false)]` - this property is (not) writeable
* `[Computed]` - this property is computed and should not be part of updates
Limitations and caveats
-------
### SQLite
`SQLiteConnection` exposes an `Update` event that clashes with the `Update`
extension provided by Dapper.Contrib. There are 2 ways to deal with this.
1. Call the `Update` method explicitly from `SqlMapperExtensions`
```Csharp
SqlMapperExtensions.Update(_conn, new Employee { Id = 1, Name = "Mercedes" });
```
2. Make the method signature unique by passing a type parameter to `Update`
```Csharp
connection.Update(new Car() { Id = 1, Name = "Maruti" });
```