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 previously not supported in Entity Framework Core:
- Raw store access APIs: Support for ad hoc mapping of arbitrary types #1862
- Stored procedure mapping support #245
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 EF Core
- Mapping is 30% faster