I'm using EF5 with Oracle Database.
I have a DBlink between two databases where I have permission to write and read specifics tables.
I'ts possible to add this objects as a table im my entity model?
The image bellow is showing my connection:
Related
I need to migrate data from many xmls to a sql server db and and it has to be done in a transactions.
I thought about EF and dbContext as it's a UOW in it's own right.
My question is
Can you do Database First at run time?
What I want to do is Read all tables from db store in class/dataset and map the db.column to equivalent in xml file and commit.
This has to work in such a way that if a table is added or column added it will work without any code changes as it is driven by db.
The problem I face is that with Db generated from model if a new column is required somebody later on "unfamiliar with EF" as to add the column "manual job".
I can do what I want with raw ado.net by reading db schema and mapping to a dataset but wondering if I could do it using EF.
Hope all clear
any suggestions
Yes you can.
You can use Entity Framework Power Tools which allows you to create Code-First file from Database of yours as you start like Code-First.
Or, you can use Database-first approach also. It's not that hard.
If you try to use database-first approach, please read my trial-and-error experience: post1, post2
I'm using VS2012 and creating a sample Entity Framework project that reads and writes to some tables that are used for import purposes. and do not have PK's or FK's in them - just null/notnull on the columns.
Can/should EF be made to insert records on these tables without that cryptic error:
Unable to update the EntitySet because it has a DefiningQuery
and no element exists in the
element to support the current
operation.
Or should I be looking elsewhere for database I/O?
Thanks!
Corey.
Is there a way to prevent Entity Framework Code-First from deleting my database diagrams when it is re-building my database?
Without using DropCreateDatabaseIfModelChanges to create your database you can use SQL Migrations
http://www.hanselman.com/blog/EntityFrameworkCodeFirstMigrationsAlphaNuGetPackageOfTheWeek10.aspx. It won't drop the database and will generate alter commands (Incremental database development) . So you can keep your diagram and existing data.
We are testing EF 4.1 against DB2 tables on a Main Frame.
We are now able to generate EF models from DB2 tables and retrieve data :)
When we generate the EF model some relationships are included in the model and some are missing. It appears that the ones that are missing are composite keys.
Is this a limitation in EF that it is not able to handle composite keys?
Is it possible add the relationship manually to the model?
We fixed this by manually editing the edmx files.
We have an application that creates new tables at runtime, but always with the same table schema. The only thing that varies from one of these tables to the next is the table name. Is it possible to access these tables using Entity Framework, specifying which table to access by name?
Entity Framework is not designed for DDL, it's an ORM tool for data access. You would want to use a simple ADO.NET query to create/drop the table.
Creating and dropping tables for every user session will make your log file grow very big very fast. I would consider carefully the reasons you think this is necessary. If the data is temporary, why not save the Session ID in each row and truncate the table on a daily basis?
UPDATE:
No, not really. The Entity Data Model is not dynamic, it's a static XML document that describes the structure of the database. If you want to interact with a table with a dynamic name, you're going to have to stick to "classic" ADO.NET.
With Linq to SQL I guess it would be possible with a stored procedure taking the table Name as a parameter.
A nice post about SP in L2SQL: http://weblogs.asp.net/scottgu/archive/2007/08/16/linq-to-sql-part-6-retrieving-data-using-stored-procedures.aspx
I don't know if that feature exists in EF.