I am using a stored procedure with an EF 4 model.
To accomplish this I'm going through the following steps:
I add the stored procedure to my Model Store by Updating from the database and selecting it.
Added a function import to point to the stored procedure
The stored procedure returns the result of a query joining multiple tables etc so in the "Returns Collection Of" area I specify a Complex Type and use the Get Column Information button below to generate the complex type returned.
Here is where my issue arises: when I use the "Generate Database From Model" option, it removes the stored procedure mapping from the Model Store.
My question is:
How can I use the "Generate Database From Model" option but ignore the Stored Procedures mapping?
In the model properties there is a "Database Generation Workflow" that is TablePerTypeStrategy but apparently this has the added effect of removing stored procedures from the model store.
I am using model first but also mapping stored procedures to function imports. Unfortunately when I make updates to the model and try to generate the database from the model, it removes my stored procedures and unmaps my function imports.
To get around this, I do an undo after I generate the database from the model on the EDMX (and keep the updated sql script). This updates the database just fine for me and restores my stored procedures and function imports as well.
These two approaches should not be used together! Use either database first (Update model from database) or model first (Generate database from model). I'm even surprised that it didn't delete your stored procedures in the database as well.
When you select Generate database from model it deletes whole storage description and mapping from your EDMX and generates a new one.
Related
I am new to Informix stuff and I have a legacy database (IBM Informix) and there are thousands of stored procedures written. Now I am trying to create the model class using Entity framework database first approach.
The problem I am facing now is;
When I am trying to add stored procedures from Update Model from Database, noting is list down in the Stored Procedures and Functions. Further I have checked with the server and found that all stored procedures are stored in sysprocedures table.
My questions are;
How can I import these procedures into Entity framework?
Is it possible to invoke stored procedure without importing?
I'm working on a project that works with datasets, but now will be with Entity Framework(any version).
My idea is to do the following
Reuse stored procedures (only selects with parameters - one or more tables)
To insert, delete and update will use Entity Framework
What is the best way (fast, not complex) to create INSERT UPDATE DELETE for those stored procedures?
I tried with context.SaveChanges but apparently does not work with imported SQL Server stored procedures. Any ideas for this project?
We currently have a system with quite large database and stored procedures are used both for CUD and querying. DataSets are used to retrieve the results from the SP querys.
Now we are looking into developing another project against the same database using Entity Framework. When querying the database, the stored procedures often perform a lot of joins to gather some fields not in the target table, but data from the joined tables that is needed by the client in some way. When using DataSets, all the fields returned by the SP was included in the DataTable. So the DataTable doesn't actually match the target database table.
What is the correct way of handling this scenario in EF? When creating my model, the entities are mapped to each table which as mentioned above only sometimes matches the result of the SP. Can I add the "additional" fields of the SP query result to the entity class as properties and have them filled by the query but with these properties being excluded when it comes to CUD on the specific entity type? Seems like the EF-way, if queried through LINQ to Entities and not SPs, would be to have entity instances with relational properties to the joined entities so that using those "additional" properties would be done by navigating the relational properties?
You can define an arbitrary complex type (just a class that's generated for you, to match the columns and datatypes returned by the stored procedure) as the return type for your stored procedure in Entity Framework (as of version 4 and newer) - no problem here.
See Stored Procedures in the Entity Framework for a great explanation of all things related to using stored procedures in Entity Framework.
is there a way, how to save EF (STE) entities in to temporary tables?
I'm trying to achieve this:
1) save my STE to temporary tables
2) run some stored procedures on them
3) depending on result from procedures, do something else..
Thank you.
EF will not handle this. EF saves the entity to table(s) defined in mapping but the mapping is defined at design time. You cannot decide to save the entity to other table at runtime through EF without changing its mapping and that would be highly inefficient - changing mapping at runtime is not a supported use case so it is quite complicated and moreover applying a new mapping is the most expensive operation in EF.
You need just another stored procedure to insert your data to temporary table. Depending on the logic you expect you can either map that procedure to insert operation for the entity (but in such case your procedure will be used every time you insert a new entity) or simply execute it directly.
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.