I am trying to work with EF, for the first time ever. I'm not sure I fully understand EF yet.
I already have a database with data in it, so I've generated my models from DB.
Our current setup runs EVERYTHING through stored procedures, even selects.
However, unless I'm mistaking, the models select directly into the tables, when I have generated them.
Can I change this behaviour, so it calls the select procedure instead?
No - at least with EF4. I can't speak for EF5
You can use stored procedures to insert and update, but those stored procedures must have all the parameters EF expects, so you're probably going to have to wrap your existing procedures in new procedures.
For select, you can use a FunctionImport and ExecuteFunction to populate an Entity.
Related
We have a large database and we do manipulations on it ever day by using the basic mysql queries.
Can anyone please tell me, what is the use of Mysql Stored Procedures?
The real use of the Stored Procedures comes into picture when have any application accessing database.
For example: Imagine that you have written all your database operations in the form of queries in your data access code.
Suppose, that you need to make any change to query , then you need to rebuild and redeploy the entire application in order see your changes.
But, if you are using stored procs and refering them in application, you can just make changes in your database with out need for redeploying the application.
So, obviously better security , maintainability and much more
Note: This is one scenario where stored procs are better than normal queries.
Usage of Stored Procs also avoids SQL Injection Attacks
In very simple words, stored procedures allow you to store your quires along with database, you can combine multiple quires in single procedure. now whenever you want to execute those quires just "CALL yourProcedure;"
Need to perform specific query daily ?
Read about MySQL events = stored procedures with scheduling capability !
https://dev.mysql.com/doc/refman/5.1/en/events.html
I'm working on an order system that can have anywhere from 1 to 200+ orders in it. Right now we have a loop that loops through each order and inserts it into the database. Would it make sense to use SqlBulkCopy? Would using it degrade performance on small orders? Are there any other techniques to speed up inserts?
Thanks!
Basically there are several things you can do.
using SqlBulkCopy.WriteToServer which doesn't work great together with EF, however there are several attempts to create extensions
using a stored procedure which will take one big record and split it according to some logic
using table-typed stored procedure parameters and do one call to the stored procedure (and several insert ... select inside the stored procedure)
Overall, I prefer third option.
Check this question Entity Framework Stored Procedure Table Value Parameter
Sometimes an application requires quite a few SQL queries before it can do anything useful. I was wondering if there is a way to send those as a batch to the database, to avoid the overhead of going back and forth between the client and the server?
If there is no standard way to do it, I'm using the python bindings of MySQL.
PS: I know MySQL has an executemany() function, but that's only for the same query executed many times with different parameters, right?
This process works best on inserts
Make all you SQL queries into Stored Procedures. These eventually will become child stored procedures
Create Master Store procedure to run all other Stored Procedures.
Modify master Stored procedure to accept values required by child Stored Procedures
Modify master Stored procedure to accept commands using "if" statements to know which
child stored procedures to run
If you need return data from Database use 1 stored procedure at the time.
I have searched through the internet, and understand that the only way to change the body of a store procedure is by dropping and creating it again. There seems nothing wrong with the mechanism but if I have a client application (or thousands of distributed clients) that keeps invoking the store procedure to update some data on the server database, dropping the procedure would result in data lost and/or corruption.
I'm thinking if there is a syntax like "CREATE PROCEDURE IF EXIST..." or something functions similarly so the update operation would be carried out smoothly. Yet I didn't find such thing being available in MySQL.
So how do you guys think this issue can be addressed? Awesome thoughts?
You cannot modify a stored procedure (though you can change its characteristics) in MySQL. From the ALTER PROCEDURE page.
This statement can be used to change the characteristics of a stored
procedure. More than one change may be specified in an ALTER PROCEDURE
statement. However, you cannot change the parameters or body of a
stored procedure using this statement; to make such changes, you must
drop and re-create the procedure using DROP PROCEDURE and CREATE
PROCEDURE.
While it is possible to lose data while performing this update (though it should be a relatively small window), it's unlikely that your data will be corrupted. I'd take a look at message queuing technologies if your system needs to be guarded against data loss from database downtime.
I have a project with a formidable data access layer using LinqtoSQL for just about anything touching our databases. I needed to build a helper class that bridges some common crud operations from CLSA objects to LinqToSql ones. Everything has been operating swimmingly until I needed to do a truncate on a table and all I had were “delete” methods.
Uh-oh. A quick search reveals that some people are using YourContext.ExecuteCommand(), which is nice and all, but I am trying to go “t-sql-less” as much as possible these days.
Is there a LINQ way to perform a truncate on a table? Or am I just clueless?
This is not possible without doing a custom T-SQL query. Doing a .Delete() and SubmitChanges afterwords would, as you probably already know, result in a DELETE statement.
Of course you could create a stored procedure that truncates the table, and then call the procedure from LINQ, but that isn't really what you're looking for I believe.
You can do something like this:
yourDataContext.ExecuteCommand("TRUNCATE TABLE YourTable");