Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
799 views
in Technique[技术] by (71.8m points)

entity framework - Get Model schema to programmatically create database using a provider that doesn't support CreateDatabase

I'm using the SQLite provider for Entity Framework 5 but it doesn't support CreateDatabase and thus cannot auto create the database. (Code First)

Is there a way I can obtain the Model schema at runtime so that I can create the SQL "CREATE TABLE" command myself?

If not at runtime, some other way to obtain the schema so I know how to create the table properly?

Thanks!

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Answer

0 votes
by (71.8m points)

A) As for obtaining the model schema at runtime part

(all are earlier posts of mine)

See this one How I can read EF DbContext metadata programmatically?

And How check by unit test that properties mark as computed in ORM model?

Also this one for a custom initializer Programmatic data transformation in EF5 Code First migration

Having said that...

The problem I see is where and at what point you actually have the data available.
Actually I'm quite sure you won't be able to do that at any time.
Because to be able to extract that info you need to have a DbContext running - so db has to be constructed etc. etc.

In the initializer maybe - but using different ways to get that info - the above is not available.

B) The other way would be to go the way of implementing a provider, generator etc. (e.g. this post).
That way you should get all that info just at the right time from the EF/CF itself.
However I haven't played with that much.

For more info you can check the EF source code

This is more of a 'gathered info' so far - in case it helps you get anywhere with it. Not really a solution. I'll add some more tomorrow.

EDIT:

To get the real database metadata, look into the other DataSpace, this should get you to the right place...
(note: things tend to get less exact from here - as obviously there isn't the right official support)

var ssSpaceSet = objectContext.MetadataWorkspace.GetItems<EntityContainer>(DataSpace.SSpace).First()
    .BaseEntitySets
    .First(meta => meta.ElementType.Name == "YourTableName");

If you look up in debugger, Table property should have the real table name.
However, reflection might be required.


How I can read EF DbContext metadata programmatically?
How check by unit test that properties mark as computed in ORM model?
Programmatic data transformation in EF5 Code First migration
Entity Framework MigrationSqlGenerator for SQLite
http://entityframework.codeplex.com/
Entity Framework - Get Table name from the Entity
ef code first: get entity table name without dataannotations
Get Database Table Name from Entity Framework MetaData
http://www.codeproject.com/Articles/350135/Entity-Framework-Get-mapped-table-name-from-an-ent


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...