I am trying to do all my DB access through LINQ. For example, I am
trying to delete a record from the JobQueue table. There’s a couple
ways I could do this:
1. Method 1 – The disadvantage is that it makes 2 calls to the DB: one
to get the record and then one to delete it:
using (LogicDataConte xt ctx = new LogicDataContex t(m_strConnect) )
{
JobQueue jq = ctx.JobQueues.S ingle(queue =queue.JobQueue No ==
queueNo);
ctx.JobQueues.D eleteOnSubmit(j q);
ctx.SubmitChang es();
}
2. Method 2 – The disadvantage is that I’m writing SQL directly, which
I don’t want to do. In fact, it’s the whole reason I’m using LINQ.
using (LogicDataConte xt ctx = new LogicDataContex t(m_strConnect) )
{
string str = "Delete JobQueue WHERE JobQueueNo = " + queueNo;
ctx.ExecuteComm and(str);
}
3. Method 3 – This doesn't work because it throws an exception: "Row
not found or changed." It doesn't make two trips to the DB like
method 1, but instead tries to attach a JobQueue to the data context.
But will only work if all the column values are exactly the same as
the values in the DB:
using (LogicDataConte xt ctx = new LogicDataContex t(m_strConnect) )
{
JobQueue jq = new JobQueue() { JobQueueNo = requestQueueNo };
ctx.JobQueues.A ttach(jq, false);
ctx.JobQueues.D eleteOnSubmit(j q);
ctx.SubmitChang es();
}
Is there a better way? I think LINQ should have a built in function
to delete a record using the primary key.
I guess if I was going to use the second method, I could write a
helper function that would use reflection to create the DELETE
statement using the table name and the fact that the primary key
column property has an attribute on it like this:
[Column(Storage= "_JobQueueN o", AutoSync=AutoSy nc.OnInsert,
DbType="Int NOT NULL IDENTITY", IsPrimaryKey=tr ue,
IsDbGenerated=t rue)]
Thanks in advance,
John 0 3719 This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics |
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Hello people:
First of all forgiveness for my English.
I am working with Linq to SQL, Visual Studio 2008 and SQL Server 2000.
When you delete a record and then go back to Insert (ie, insert a record
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to run
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Hello people:
First of all forgiveness for my English.
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When you delete a record and then go back to Insert (ie, insert a record
with the same primary key)
and I run SubmitChange it generates an key duplicate exception.
I am reviewing the SQL commands generated by linq, and I see that attempts
to run
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