How to lock tabel with LINQ to SQL (转载) - 未名空间MITBBS历史存档

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How to lock tabel with LINQ to SQL (转载)

How to lock tabel with LINQ to SQL (转载)# Database - 数据库

f*e2009-02-17 08:02

1 楼

【以下文字转载自 DotNet 讨论区】
发信人: flyfire (flyfire), 信区: DotNet
标题: How to lock tabel with LINQ to SQL
发信站: BBS 未名空间站 (Mon Feb 16 23:56:26 2009)
Here is the table:
Col1, Seqno, ...
A, 1, ...
A, 2, ...
A, 3, ...
B, 1, ...
C, 1, ...
(Col1 + seqno) is the primary key.
When I use LINQ to insert a new record, I need to calculate next seqno. For
example, if I want to insert a new row with value A in col1, the seqno will
be 4.
It is not hard to do the calculation. But the problem is that I need to lock
the

B*g2009-02-17 08:02

2 楼

linq还不会。
不过你这个一般要用sp或者trigger

【在 f*****e 的大作中提到】

: 【以下文字转载自 DotNet 讨论区】
: 发信人: flyfire (flyfire), 信区: DotNet
: 标题: How to lock tabel with LINQ to SQL
: 发信站: BBS 未名空间站 (Mon Feb 16 23:56:26 2009)
: Here is the table:
: Col1, Seqno, ...
: A, 1, ...
: A, 2, ...
: A, 3, ...
: B, 1, ...

s*m2009-02-17 08:02

3 楼

Can Rank() or Row_Number() etc help? I don't know if and how they can be
expressed in LINQ

B*g2009-02-17 08:02

4 楼

he is asking if multiply insert happen at same time.

【在 s**m 的大作中提到】

: Can Rank() or Row_Number() etc help? I don't know if and how they can be
: expressed in LINQ

s*m2009-02-17 08:02

5 楼

seems can not realize lock while manipulate dataset at client side code. you
can use try catch
try {
db.SubmitChanges();
}
catch (OptimisticConcurrencyException e) {
// You have your choice of RefreshMode to resolve concurrency conflicts.
// You can KeepChanges, KeepCurrentValues, OverwriteCurrentValues.
e.Resolve(RefreshMode.OverwriteCurrentValues);
db.SubmitChanges();
}
let us know if it works. this is a learning process for me too

t*n2009-02-17 08:02

6 楼

This looks like a bad database design to me.
But, anyway, I don't have to maintain this thing.
never used LINQ before. But using SQL, you can do this.
begin tran
select * from TABLE1 with (tablock, updlock, holdlock) where 1=2
then the TABLE1 will be locked until you commit or rollback the transaction.

【在 f*****e 的大作中提到】

B*g2009-02-17 08:02

7 楼

1. insert one record the whole table is locked?
2. does this need more previldges than DML?
明天俺要在oracle里做这件事，头说不care，就让insert fail了得了。

transaction.

【在 t****n 的大作中提到】

: This looks like a bad database design to me.
: But, anyway, I don't have to maintain this thing.
: never used LINQ before. But using SQL, you can do this.
: begin tran
: select * from TABLE1 with (tablock, updlock, holdlock) where 1=2
: then the TABLE1 will be locked until you commit or rollback the transaction.

t*n2009-02-17 08:02

8 楼

don't really understand what do you mean. The way I did it is by query hints
of SQL Server. I don't know a lot about Oracle. I heard 'for update' MAY be
the equivalent.
I don't think so. anyone who can update the table can do it.

【在 B*****g 的大作中提到】

: 1. insert one record the whole table is locked?
: 2. does this need more previldges than DML?
: 明天俺要在oracle里做这件事，头说不care，就让insert fail了得了。
:
: transaction.

B*g2009-02-17 08:02

9 楼

insert 1 record lock the whole table may not be good.

hints
be

【在 t****n 的大作中提到】

:
: don't really understand what do you mean. The way I did it is by query hints
: of SQL Server. I don't know a lot about Oracle. I heard 'for update' MAY be
: the equivalent.
: I don't think so. anyone who can update the table can do it.