如何使用实体框架获取行的序列号？

发布于 2024-12-12 01:03:32 字数 225 浏览 0 评论 0原文

我有 SQL 查询：

WITH OrderedRecs AS
(select ROW_NUMBER() OVER(ORDER BY RecID) as seqNumber,* from Records where RecordGroupID=7)
SELECT * FROM OrderedRecs where RecordID=35

如何使用实体框架获得相同的结果？

原文

I have SQL query:

WITH OrderedRecs AS
(select ROW_NUMBER() OVER(ORDER BY RecID) as seqNumber,* from Records where RecordGroupID=7)
SELECT * FROM OrderedRecs where RecordID=35

How do I get the same result using entity framework?

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无妨# 2024-12-19 01:03:33

一个纯粹的 LINQ 解决方案是：

records.Where(rec => rec.RecordGroupID == 7)
    .OrderBy(rec => rec.RecId).AsEnumerable()
    .Select((rec, i) => new { i, rec })
    .Where(anon => anon.i == 35)
    .Select(anon => anon.rec).First()

但是您必须对以下事实感到满意：与第一个条件匹配的所有记录都是在本地获取的。

编辑：

评论后：可能类似于：

IEnumerable<SortedRecord> GetSortedRecords(IQueryable<Record> records
    , Func<SortedRecord, bool> sortedRecordPredicate)
{
    return
      records.Where(rec => rec.RecordGroupID == 7)
        .OrderBy(rec => rec.RecId).AsEnumerable()
        .Select((rec, i) => new SortedRecord{ Sequence = i, Record = rec })
        .Where(sortedRecordPredicate);
}

var result = GetSortedRecords(records, rec => rec.Record.RecordID = 35);

其中 SortedRecord 显然现在是一种类型，它使您能够输入各种条件。（未检查语法）。

一种完全不同的方法是在 WITH 子句中创建查询视图。

A pure LINQ solution would be:

records.Where(rec => rec.RecordGroupID == 7)
    .OrderBy(rec => rec.RecId).AsEnumerable()
    .Select((rec, i) => new { i, rec })
    .Where(anon => anon.i == 35)
    .Select(anon => anon.rec).First()

But than you must be happy with the fact that all records matching the first condition are fetched locally.

Edit:

After you comments: Propably something like:

IEnumerable<SortedRecord> GetSortedRecords(IQueryable<Record> records
    , Func<SortedRecord, bool> sortedRecordPredicate)
{
    return
      records.Where(rec => rec.RecordGroupID == 7)
        .OrderBy(rec => rec.RecId).AsEnumerable()
        .Select((rec, i) => new SortedRecord{ Sequence = i, Record = rec })
        .Where(sortedRecordPredicate);
}

var result = GetSortedRecords(records, rec => rec.Record.RecordID = 35);

Where SortedRecord, obviously, is a type now, which enables you to enter all kinds of conditions. (syntax not checked).

A completely different approach would be to make a view of the query within the WITH clause.

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