问题
I am porting our product's database to SQLite from another product that supported Guids. As we know, SQLite does not support Guids. I've got created an entity framework 6 model from my database (database first) and I need to build a query from C# that compares the Guid to one passed from the code.
The thing is I can't find any documentation on how the SQLite Entity Framework provider handles Guids. A web search didn't find anything useful for me, either. Just questions about using Entity Framework with SQLite.
Can anybody point me to the documentation, or maybe tell me how to work with Guids in a SQLite database through an EF6 model?
回答1:
It appears that this was resolved in 1.0.95 however broken again in 1.0.97. The solution is to set the BinaryGUID property on the connection string to true and set the following environment variable (before you make the connection)
Environment.SetEnvironmentVariable("AppendManifestToken_SQLiteProviderManifest",";BinaryGUID=True;");
Data Source=c:\mydb.db;Version=3;BinaryGUID=True;
https://www.connectionstrings.com/sqlite/
回答2:
I finally have an answer to this problem.
My problem is that the SQLite Entity Framework 6 provider doesn't handle converting literal Guids in your code into SQL properly. That is, a Linq expression of the form
context.MyEntity.Where( x => x.GuidColumn == new Guid("xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx") )
Gets converted into the following SQL:
SELECT GuidColumn, Column1, Column2, . . . Column n
FROM MyEntity AS Extent1
WHERE Extent1.GuidColumn = 'xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
This is wrong, since the value stored in the column is a byte array.
According to this problem report on the SQLite site, it turns out that the SQLite team considers this to be a bug in the provider and they are working to fix it in release 1.0.95.0. I don't know when that will be released, but at least they recognize it as a problem and are going to fix it.
来源：https://stackoverflow.com/questions/27279177/how-does-the-sqlite-entity-framework-6-provider-handle-guids