CODEWITHSUNDEEP
c#esent
jgauffin
jgauffin

Reputation: 101150

Check if a database exists

How do I check if a database exist in esent?

I can use Api.JetAttachDatabase and Api.JetOpenDatabase to open an existing database and use Api.JetCreateDatabase to create a new one. But I can't find an API that allows me to check whether a DB exists.

Do I really have to catch an exception from Api.JetAttachDatabase to detect if the db exist?

Upvotes: 0

Views: 537

Answers (2)

Martin Chisholm
Martin Chisholm

Reputation: 471

I'll apologize for the lack of details because I'm on vacation and don't have the source code handy. :) This is off the top of my head.

o Api.JetAttachDatabase calls JetApi.JetAttachDatabase.

o JetApi.JetAttachDatabase returns an error code (which is what you want!).

o Api.JetAttachDatabase converts that to an exception.

The biggest problem may be that JetApi.Xxx may not be public. It may be internal-only. I'd have to ask the original author if there's a reason for it not be public. If there isn't one, I can make the change in a future release of ManagedEsent.

Sorry for the uncertain answer.

Hey, I was just wondering: what about a CLR function, like File.Exists() ?

-martin

Upvotes: 1

Bruce Burge
Bruce Burge

Reputation: 154

You shouldn't have to catch the exception, the return type returns an JET_ERR type that will let you know if there is a problem, if you are looking for a simple bool check, I believe you may be out of luck, or have to write your own.

Source :

http://msdn.microsoft.com/en-us/library/gg294074.aspx

http://msdn.microsoft.com/en-us/library/gg294092.aspx

const JET_errSuccess = 0;

result = JetCreateDatabase(...);

if(result != JET_errSuccess)
{
  //throw error
}

Upvotes: 0

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