Execute stored procedures with Entity Framework Core

DbContext extension with LoadStoredProc method which creates an IStoredProcBuilder to build a stored procedure with a custom mapping strategy using the provided DbDataReader extension.

The method handles :

Extra column in result set
Extra property in model
Null values in result set
Underscores in result set column names ("column_name" is mapped to ColumnName property)
Int (db) to enumeration (result model) mapping

Example

List<Model> rows = null;

ctx.LoadStoredProc("dbo.ListAll")
   .AddParam("limit", 300L)
   .AddParam("limitOut", out IOutParam<long> limitOut)
   .Exec(r => rows = r.ToList<Model>());

long limitOutValue = limitOut.Value;

ctx.LoadStoredProc("dbo.ReturnBoolean")
   .AddParam("boolean_to_return", true)
   .ReturnValue(out IOutParam<bool> retParam)
   .ExecNonQuery();

bool b = retParam.Value;

ctx.LoadStoredProc("dbo.ListAll")
   .AddParam("limit", 1L)
   .ExecScalar(out long l);

API

DbContext

IStoredProcBuilder LoadStoredProc(string name)

IStoredProcBuilder

IStoredProcBuilder AddParam<T>(string name, T val) // Input parameter
IStoredProcBuilder AddParam<T>(string name, T val, out IOutParam<T> outParam, int size, byte precision, byte scale) // Input/Ouput parameter
IStoredProcBuilder AddParam<T>(string name, out IOutParam<T> outParam, int size, byte precision, byte scale) // Ouput parameter
IStoredProcBuilder ReturnValue<T>(out IOutParam<T> retParam, int size, byte precision, byte scale)
IStoredProcBuilder SetTimeout(int timeout)
Task               ExecAsync(Func<DbDataReader, Task> action, CancellationToken cancellationToken)
Task<int>          ExecNonQueryAsync(CancellationToken cancellationToken)
Task               ExecScalarAsync<T>(Action<T> action, CancellationToken cancellationToken)

DbDataReader

Task<List<T>>                        ToListAsync<T>()
Task<Dictionary<TKey, TValue>>       ToDictionaryAsync<TKey, TValue>(Func<TValue, TKey> keyProjection)
Task<Dictionary<TKey, List<TValue>>> ToLookupAsync<TKey, TValue>(Func<TValue, TKey> keyProjection)
Task<HashSet<T>>                     ToSetAsync<T>()
Task<List<T>>                        ColumnAsync<T>()
Task<List<T>>                        ColumnAsync<T>(string columnName)
Task<T>                              FirstAsync<T>()
Task<T>                              FirstOrDefaultAsync<T>()
Task<T>                              SingleAsync<T>()
Task<T>                              SingleOrDefaultAsync<T>()

All these methods have a corresponding async method : ToListAsync, ToDictionaryAsync, ...

Installation

Install-Package StoredProcedureEFCore

Why ?

Stored procedure execution was not supported in entity framework core:

It is now supported since EF Core 2.1 but this library has few advantages compared to FromSql:

Extra property in the model won't throw an exception. The property keeps its default value
The interface is easier to use. Output parameters and return values seem difficult to use with EFCore
Mapping is 30% faster

coldacid/StoredProcedureEFCore