I have a SQL Server view CyclesList on the table Cycle. Cycle table contains a few columns, and CyclesList view add some more data that can be computed on database level.
And now, I have a NHibernate mapping that points to CyclesList:
<class name="Cycle" table="CyclesList">
However, I would still like to work with Cycle class, and perform Create/Update operations , but I have to use stored procedure that will access Cycle table directly. Is there a way to achieve it in NHibernate? I would appriciate a sample mapping/links to resources with samples. Thanks
You find some information in the docs under "Native-Sql -> Custom SQL for create, update and delete". Basically, you need the "sql-insert", "sql-delete" and "sql-update" elements in the mapping file.
There is also an example on Ayendes blog.
Related
In informatica power center I want to create one mapping and three session and query of each session is different so how I do this
You can easily do this. You need to create three sessions and change above properties using same mapping.
And pls note, you can change SQL overwrite, LKP SQL Overwrite, file name, source table and target table/schema, parameter file name.
If you want to change the SQL, just edit the session, select source and change the overwrite SQL. Pls note the SQL should have same number of columns and order like original mapping.
You should actually create three mappings, each one implementing the required logic. Next, create a Workflow and add a session for each mapping. Connect the arrows to set the execution order (sequentially or in parallel). And you're done!
I have a field in Cosmos DB which is mapped as an number, but it should be a string. I'd like to alter the schema in-place without reloading the data, is this possible with a query in the same way it can be achieved in SQL?
ALTER TABLE EVENTS
MODIFY COLUMN eventAmount varchar;
Have consulted the docs but they only reference simple SQL commands.
DocumentDB is schemaless. There is no structure defined outside documents themselves so each document has their own schema. If you want to enforce some documents follow a certain structure, then that must be enforced by yourself in your application logic.
So, this means you can not "alter schema" for collection to change data types.
What you can and should do, is to fix documents which you consider having wrong schema by updating them. Query docs where eventAmount is stored as JS number and save the document with the value stored as a corresponding javascript string instead.
I'm using Fluent NHibernate (and I'm a newbie). I have mapped a read-only table that already exists in the database (it's actually a view in the db). In addition, I have mapped new classes for which I want to create tables using SchemaExport.Create().
In my fluent mapping, I have specified "ReadOnly()" to mark the view as immutable. However, when I execute SchemaExport.Create(), it still tries to create the table so I get the error "There is already an object named 'vw_Existing'".
Is there a way to prevent NHibernate from trying to create that specific table?
I supposed I could export and modify the sql (SetOutputFile), but it would be nice to use SchemaExport.Create().
Thanks.
You're looking for
SchemaAction.None();
I have collection of object that contain several properties. I need to update this object list in the data base, now, i am looking for the best way to do it. Until now i use to work with xml, i created xml structure from the object list and send it to the data base and in the data base i parsed the xml and insert/update the tables i need.
Can you please suggest me better way to do that?
Sql 2005, MVC 2, C#4.
Thanks..
From what you've written, you'd probably be best to just loop through your collection and save each one using ADO.Net. That avoids the overhead of serializing your data to XML and then parsing it again on the database side.
That being said, unless this data is being generated by your software, you probably should be looking at something like SSIS or BCP for moving large amounts of data into SQL Server from whatever source your program is getting the data.
I've been writing a Library management Java app lately, and, up until now, the main Library database is stored in a .txt file which was later converted to ArrayList in Java for creating and editing the database and saving the alterations back to the .txt file again. A very primitive method indeed. Hence, having heard on SQL later on, I'm considering to port my preexisting .txt database to mySQL. Since I've absolutely no idea how SQL and specifically mySQL works, except for the fact that it can interact with Java code. Can you suggest me any books/websites to visit/buy? Will the book Head First with SQL ever help? especially when using Java code to interact with the SQL database? It should be mentioned that I'm already comfortable with using 3rd Party APIs.
View from 30,000 feet:
First, you'll need to figure out how to represent the text file data using the appropriate SQL tables and fields. Here is a good overview of the different SQL data types. If your data represents a single Library record, then you'll only need to create 1 table. This is definitely the simplest way to do it, as conversion will be able to work line-by-line. If the records contain a LOT of data duplication, the most appropriate approach is to create multiple tables so that your database doesn't duplicate data. You would then link these tables together using IDs.
When you've decided how to split up the data, you create a MySQL database, and within that database, you create the tables (a database is just something that holds multiple tables). Connecting to your MySQL server with the console and creating a database and tables is described in this MySQL tutorial.
Once you've got the database created, you'll need to write the code to access the database. The link from OMG Ponies shows how to use JDBC in the simplest way to connect to your database. You then use that connection to create Statement object, execute a query to insert, update, select or delete data. If you're selecting data, you get a ResultSet back and can view the data. Here's a tutorial for using JDBC to select and use data from a ResultSet.
Your first code should probably be a Java utility that reads the text file and inserts all the data into the database. Once you have the data in place, you'll be able to update the main program to read from the database instead of the file.
Know that the connection between a program and a SQL database is through a 'connection program'. You write an instruction in an SQL statement, say
Select * from Customer order by name;
and then set up to retrieve data one record at a time. Or in the other direction, you write
Insert into Customer (name, addr, ...) values (x, y, ...);
and either replace x, y, ... with actual values or bind them to the connection according to the interface.
With this understanding you should be able to read pretty much any book or JDBC API description and get started.