0

我目前在我的项目中有以下代码

   public List<PermissionValue> GetUnderlyingPermissionsForUser(string userName, int guiPermissionTypeId, int productTypeId)
    {
        using (CliVeEntities db = new CliVeEntities())
        {             
            var listUnderlyings = (from gui in db.GuiPermissionUnderlying
                                join bue in db.BranchUsersExternal on gui.BranchUsersId equals bue.BranchUsersID     
                                join bu in db.BranchUsers on bue.BranchUsersID equals bu.BranchUsersId
                                where bu.UserName == userName && gui.ViewTypeId == guiPermissionTypeId
                                && gui.UnderlyingId.HasValue
                                && !gui.SectorId.HasValue
                                && gui.ProductTypeId == null
                                && gui.ProductGroupId == null
                                select new PermissionValue { Id = gui.UnderlyingId.Value, Visible = gui.value}).ToList<PermissionValue>();


            var listUnderlyingsProductGroup = (from gui in db.GuiPermissionUnderlying
                                                join bue in db.BranchUsersExternal on gui.BranchUsersId equals bue.BranchUsersID
                                               join bu in db.BranchUsers on bue.BranchUsersID equals bu.BranchUsersId
                                               join pg in db.ProductGroup on gui.ProductGroupId equals pg.ProductGroupId
                                               join pt in db.ProductType on pg.ProductGroupId equals pt.ProductGroupId
                                               where bu.UserName == userName && gui.ViewTypeId == guiPermissionTypeId
                                               && gui.UnderlyingId.HasValue
                                               && !gui.SectorId.HasValue
                                               && pt.ProductTypeId == productTypeId
                                               select new PermissionValue { Id = gui.UnderlyingId.Value, Visible = gui.value }).ToList<PermissionValue>();




            var listUnderlyingsProductType = (from gui in db.GuiPermissionUnderlying
                                                join bue in db.BranchUsersExternal on gui.BranchUsersId equals bue.BranchUsersID
                                              join bu in db.BranchUsers on bue.BranchUsersID equals bu.BranchUsersId
                                              where bu.UserName == userName && gui.ViewTypeId == guiPermissionTypeId
                                              && gui.UnderlyingId.HasValue
                                              && !gui.SectorId.HasValue
                                              && gui.ProductTypeId == productTypeId
                                              select new PermissionValue { Id = gui.UnderlyingId.Value, Visible = gui.value }).ToList<PermissionValue>();


            var listUnderlyingsForSectors = (from gui in db.GuiPermissionUnderlying
                                             join bue in db.BranchUsersExternal on gui.BranchUsersId equals bue.BranchUsersID
                                             join bu in db.BranchUsers on bue.BranchUsersID equals bu.BranchUsersId
                                             join u in db.Underlying on gui.SectorId equals u.SectorId
                                             where bu.UserName == userName && gui.ViewTypeId == guiPermissionTypeId
                                             && !gui.UnderlyingId.HasValue
                                             && gui.ProductTypeId == null
                                             && gui.ProductGroupId == null
                                             select new PermissionValue { Id = u.UnderlyingId, Visible = gui.value }).ToList<PermissionValue>();


            var listUnderlyingsForSectorsProductGroup = (from gui in db.GuiPermissionUnderlying
                                                        join bue in db.BranchUsersExternal on gui.BranchUsersId equals bue.BranchUsersID
                                                         join bu in db.BranchUsers on bue.BranchUsersID equals bu.BranchUsersId
                                                         join u in db.Underlying on gui.SectorId equals u.SectorId
                                                         join pg in db.ProductGroup on gui.ProductGroupId equals pg.ProductGroupId
                                                         join pt in db.ProductType on pg.ProductGroupId equals pt.ProductGroupId
                                                         where bu.UserName == userName && gui.ViewTypeId == guiPermissionTypeId
                                                         && !gui.UnderlyingId.HasValue
                                                         && pt.ProductTypeId == productTypeId
                                                         select new PermissionValue { Id = u.UnderlyingId, Visible = gui.value }).ToList<PermissionValue>();

            var listUnderlyingsForSectorsProductType = (
                                                        from gui in db.GuiPermissionUnderlying
                                                        join bue in db.BranchUsersExternal on gui.BranchUsersId equals bue.BranchUsersID
                                                        join bu in db.BranchUsers on bue.BranchUsersID equals bu.BranchUsersId
                                                        where bu.UserName == userName && gui.ViewTypeId == guiPermissionTypeId
                                                        && !gui.UnderlyingId.HasValue
                                                        && gui.SectorId.HasValue
                                                        && gui.ProductTypeId == productTypeId
                                                        select new PermissionValue { Id = gui.UnderlyingId.Value, Visible = gui.value }).ToList<PermissionValue>();

            var mergeList1 = MergeAndDistinctList(listUnderlyings, listUnderlyingsProductType);
            var mergeList2 = MergeAndDistinctList(mergeList1, listUnderlyingsProductGroup);
            var mergeList3 = MergeAndDistinctList(mergeList2, listUnderlyingsForSectors);
            var mergeList4 = MergeAndDistinctList(mergeList3, listUnderlyingsForSectorsProductType);
            var resultMergeList = MergeAndDistinctList(mergeList4, listUnderlyingsForSectorsProductGroup);

            return resultMergeList;

这是我的 MergeAndDistinctList 函数的代码

 protected List<PermissionValue> MergeAndDistinctList(List<PermissionValue> listPrimary, List<PermissionValue> listSecondry)
    {
        List<PermissionValue> listMergedAndDistinct = new List<PermissionValue>();

        listMergedAndDistinct.AddRange(listPrimary);

        var filter = listPrimary.Select<PermissionValue, int>(p => p.Id);
        listMergedAndDistinct.AddRange(listSecondry.Where<PermissionValue>(p => !filter.Contains(p.Id)).Select(p => p));
        return listMergedAndDistinct;
    }

我的 GetUnderlyingsForClient() 代码的问题是它多次访问数据库。如果此方法受到很多打击，那么这可能会转化为对数据库的多次调用。

有谁知道有什么方法可以使这段代码更高效并减少我必须进行的数据库调用量。

4

2 回答 2

0

您可以Union按照以下简化模式进行查询：

(from a in As where a.Id > 0 select a)
.Union(
from a in As where a.Name == "a" select a)
.Union(
...
)
.Select(a => new { a.x, a.y })
.Distinct()

TheUnion是 MergeAndDistinctList 的合并部分，而Distinctehh 是不同的部分。好消息是： Distinct 是在投影上执行的（在您的情况下是 Id 和 Visible ）。

现在一切都应该在一个（怪物）查询中执行，而不需要由AddRangeMergeAndDistinctList 引起的中间强制执行。

看着您的查询，我觉得您可以通过结合一些条件来处理较少数量的查询，但这取决于您。

于 2012-06-24T18:46:31.927 回答
0

似乎您在同一张表上进行了很多查询（在您的情况下是 a）

要限制数据库查询，您可以在本地列表中获取所需的所有数据，并将此列表用于您的多个查询，如下所示：

var MyBaseList = db.A.ToList();

var listUnderlyings = (from a MyBaseList [...]
var listUnderlyingsProductGroup = (from a MyBaseList [...]

为了限制数据检索，过滤 MyBaseList 以仅获取以下查询使用的行。

于 2012-06-21T15:39:53.173 回答