Question

通用存储库和实体框架：我打算使用通用存储库来处理上下文的查询，并注意到（使用SQL服务器分析器）过滤器表达式没有被翻译并包含在对数据库的SQL查询中。只是想知道在使用通用存储库时是否会出现这种过载？存储库代码：

public class BaseRepositories<TEntity> where TEntity : class
{

    private readonly DbContext _CurrentObjectContext;
    private readonly DbSet<TEntity> _EntityObjectSet;

    public BaseRepositories(DbContext currentObjectContext)
    {
        _CurrentObjectContext = currentObjectContext;
        _EntityObjectSet = _CurrentObjectContext.Set<TEntity>();
    }

    public DbSet<TEntity> EntityObjectSet
    {
        get
        {
            return _EntityObjectSet;
        }
    }

    public IQueryable<TEntity> Query(Func<TEntity, bool> expression, params Expression<Func<TEntity, object>>[] navigationProperties)
    {
        var ReturnSetQueryable = _EntityObjectSet.Where(expression);
        return ReturnSetQueryable.AsQueryable();
    }

}

从资源管理器调用存储库和上下文以及SQL查询 a）使用存储库：

代码：

        var UserRepository = new BaseRepositories<user>(new DbContext());


        var UsersQuery = UserRepository.Query(v => v.name == "ajayr");

        var FirstUser = UsersQuery.FirstOrDefault();

从Sql Profiler查询：

选择 [Extent1]。[guid] AS [guid]， [Extent1]。[id] AS [id]， [Extent1]。[name] AS [name]， [Extent1]。[密码] AS [密码]， [Extent1]。[first_name] AS [first_name]， [Extent1]。[middle_name] AS [middle_name]， [Extent1]。[last_name] AS [last_name]， [Extent1]。[email_address] AS [email_address]， [Extent1]。[url] AS [url]， [Extent1]。[account_enabled] AS [account_enabled]， [Extent1]。[user_id] AS [user_id]， [Extent1]。[last_update] AS [last_update]， [Extent1]。[删除] AS [删除]， [Extent1]。[employee_id] AS [employee_id]， [Extent1]。[rec_source] AS [rec_source]， [Extent1]。[last_login_date] AS [last_login_date]， [Extent1]。[last_email_update] AS [last_email_update]， [Extent1]。[invalid_email_adr] AS [invalid_email_adr] FROM [dbo]。[users] AS [Extent1]

b）对上下文的直接查询：

代码：

       DbContext db = new DbContext();

        DbSet<user> usersset = db.Set<user>();

       var UserQueryWithFilter =  usersset.Where(v => v.name == "ajayr");

       var FirstUser = tesst.FirstOrDefault();

从Sql Profiler查询：

SELECT TOP（1） [Extent1]。[guid] AS [guid]， [Extent1]。[id] AS [id]， [Extent1]。[name] AS [name]， [Extent1]。[密码] AS [密码]， [Extent1]。[first_name] AS [first_name]， [Extent1]。[middle_name] AS [middle_name]， [Extent1]。[last_name] AS [last_name]， [Extent1]。[email_address] AS [email_address]， [Extent1]。[url] AS [url]， [Extent1]。[account_enabled] AS [account_enabled]， [Extent1]。[user_id] AS [user_id]， [Extent1]。[last_update] AS [last_update]， [Extent1]。[删除] AS [删除]， [Extent1]。[employee_id] AS [employee_id]， [Extent1]。[rec_source] AS [rec_source]， [Extent1]。[last_login_date] AS [last_login_date]， [Extent1]。[last_email_update] AS [last_email_update]， [Extent1]。[invalid_email_adr] AS [invalid_email_adr] FROM [dbo]。[用户] AS [Extent1] 在哪里'ajayr'= [Extent1]。[name]

Answer 1

您提供的是函数，而不是表达式作为参数。我认为您需要稍微更改语法

public IQueryable<TEntity> Query(Expression<Func<TEntity, bool>> expression, params Expression<Func<TEntity, object>>[] navigationProperties)
{
    var ReturnSetQueryable = _EntityObjectSet.Where(expression);
    return ReturnSetQueryable.AsQueryable();
}

实体框架通用存储库与上下文的直接查询

1 个答案: