I have a single hosted SQL Server DB and I don't have permissions to drop it. How do I make EF create tables from my domain classes? RecreateDatabaseIfModelChanges and AlwaysRecreateDatabase try to drop DB, CreateDatabaseOnlyIfNotExists doesn't create the tables.
Thx
CreateDatabaseOnlyIfNotExists is the default strategy. It means you don't need to even set it through the Database.SetInitializer. EF Code First will check the database and if couldn't find one with the same name as your context's fully qualified name, it will create one for you.
Related
I have a recommendation from Azure to create the following index:
CREATE NONCLUSTERED INDEX [nci_wi_Transactions_71EA7D20388C3F47A9B9EBF2A1C7BA0C] ON [dbo].[Transactions] ([Client_Id]) INCLUDE ([Date], [Description], [Size], [Type]) WITH (ONLINE = ON)
Is it possible to execute this SQL directly from MSSQL without affecting my applications work?
Or do I need to apply some migrations from code-first to keep database context with the correct state anyway?
Actually, #Steve in comment answered and I checked in runtime and
Yes, it is safe to create an index directly from a database, which will not affect applications, used not changed DbContext.
I've always used the edmx file approach and just run "update from database". Now i am using Code first from existing database.
When the DBA changes the database schema, how do I update my dbcontext file and POCOs to match? Is that what migrations are for? Do I just delete everything int he models folder and re-create?
"Code-First" has two different meanings in EF. It's both a Modeling workflow and a Mapping style. You can do Code-First Mapping with Database-First Modeling. You simply regenerate your entity types after changing the database, or change them manually to match the database change. This is what's called "Code-First From and Existing Database"
I am working on a project in which I am assigned to implement database first Approach. Here, I want to know that when we initiate database first approach we map that to an existing DB, but what if I have another DB with the same structure but different data, can I use that DB by just changing the connection string ? or will it impact somehow?
It will work when you change the connection string. I recommend you select the 'Code First from database' when creating new 'ADO.NET Entity Data Model' with VS add new item.
I have created mvc3 application.
I have one .edmx already created which is based on Db1 but now
I have created a view which is based on Database2 and I need to use this view inside my project.
For that I need to update my EF .edmx file.
but when I right click and select option Update model from Database
i'm only getting all tables , view ,sps fromDb1` its obvious
But as i need to use view which is fromDatabase2how can i add it into my model.edmx` file?
please help.
If two edmx want to merge then make partial class same for both edmx file (there will be two designer classes). Add another constructor and make it parametrized, for other edmx file. Parameter to identify which edmx want to load.
Add another class file in Business layer create object of edmx partial class in this class file, Under this class when ever you want to load whom so ever edmx file pass some argument in constructor of edmx partial class constructor to identify which connection needs to open.
Pass parameter in constructor of edmx designer class, based on decided page name (custom logic or table name; That edmx will get loaded.
In web config file multiple connection strings will available for multiple edmx file.
Entity Framework does not support mapping more than one database to one model/.edmx file (see See : unify two models (edmx) with visual studio 2010)
So you'd need to create a separate .edmx file/model for the other database, and reference each model with separate contexts. You'll need 2 connection strings in your projects as well.
One "hack" might be, for i.e. MS SQL to link these two servers and expose the data from other one on first one, i.e. via view. But I think it's manageable only for few tables. With huge models this will be pain. Other databases (Firebird, Oracle, ...) support this in similar way.
What I have done , created stored procedure in db A and accessed the db B through that SP , say select * from db2.table.then create a function import for that particular SP .
This approach works well if you have both databases on same server. In case these are on different servers you can create Linked Server on B to access A using the same stored procedure approach.
Using ctx As New Entity()
ctx.Database.Connection.ConnectionString = conString
End Using
I am learning code first and I have project to be used with an existing database.
I am a bit confused of what I meant to be doing.I will explain:
Do I need to create an entityconfiguration for each table in my existing database?
Within this EntityConfiguration for each table do I need to create foreign key relationships?
Do I need to do a ToTable for each table in my existing database?
Is there any free tool "codeplex" that pointing to an existing db will generate this codeFirst stuff?
I have seem few blogs about "EF Code first with existing db" but I am not sure or was not clear to me If Need to create this stuff or I will be getting strange errors like "MyColumn_MyColum" basically as if codeFirst is trying to build some FKs or something.
can somebody clarify?
thanks a lot. I know there are few questions but if you can answer 01 or 2 that would be fine.
thanks again
If you want the code to be generated for you use database-first approach with DbContext API. Simply create EDMX file from your database and let DbContext Generator template generate all entities and context for you.
DbContext Fluent API is mainly targeted to the code-first development approach where EF will created database for you from the code you provided. It can be used with existing database but it requires much more skills and understanding of mapping wich EF can provide to you.
Generally:
You don't need to provide EntityConfiguration for each table if you follow some naming conventions (entity name is singular form of table name, all properties have the same name, primary key in table and entity is named as Id or EntityNameId, etc.).
You don't need to define relationships manually if you follow conventions with exposing navigation properties and possibly also foreign key properties. The issue can be naming of many-to-many keys and junction tables.
ToTable is needed only if your entity does not follow naming convention or if you map some advance inheritance or splitting.
EF uses a lot of default conventions which drive how the names should be defined. Conventions can be removed.
You will not do anything wrong if you define EntityConfiguration for each table - it will at least allow you learning what is needed and your mapping will be explicit / self documented.