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.
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I'm trying to use Azure Data Factory (V2) to copy data to a MongoDb database on Atlas, using the MongoDB Atlas connector but I have an issue.
I want to do an Upsert but the data I want to copy has no primary key, and as the documentation says:
Note: Data Factory automatically generates an _id for a document if an
_id isn't specified either in the original document or by column mapping. This means that you must ensure that, for upsert to work as
expected, your document has an ID.
This means the first load works fine, but then subsequent loads just insert more data rather than replacing current records.
I also can't find anything native to Data Factory that would allow me to do a delete on the target collection before running the Copy step.
My fallback will be to create a small Function to delete the data in the target collection before inserting fresh, as below. A full wipe and replace. But before doing that I wondered if anyone had tried something similar before and could suggest something within Data Factory that I have missed that would meet my needs.
As per the document, You cannot delete multiple documents at once from the MongoDB Atlas. As an alternative, you can use the db.collection.deleteMany() method in the embedded MongoDB Shell to delete multiple documents in a single operation.
It has been recommended to use Mongo Shell to delete via query. To delete all documents from a collection, pass an empty filter document {} to the db.collection.deleteMany() method.
Eg: db.movies.deleteMany({})
How can I add new columns to existing table?
I can see that Doctrine_Migration_Base has a nice method addColumn() which I could use to add new column, but it only prepares the data required for the migration.
Usually this method is called from Doctrine_Migration class (via execute() from the command line). But Doctrine_Migration looks for the migration classes in the specified directory and then executes migrations one by one.
I need a way to call addColumn() without writing the migration classes to disk.
How can I do this (except direct calling SQL altering the table)?
I'm using NHibernate Fluent Code First for c# desktop app. Is there a way to update db schema without removing existing data.
In my case I need simply add a new column with no constraints, allows nulls, and not a foreign/primary key, but I need to save all the existing data in db.
The db is Postgre 9.2 if it matters
fluentConfiguration.ExposeConfiguration(config => new SchemaUpdate(config).Execute(false, true)) updates database schema automatically and doesn't change existing data. It can only add tables or columns.
Rename and delete can be executed with FluentMigrator but then you have to manually write data migrations if you need to save your data.
I am writing a utility for myself that needs to be able to access a pair of tables in a SQL database. I used the SqlEntityConnection Type Provider and was rewarded with the data I needed from the table as easy to use entities.
One thing I noticed though was that startup and compiling of the project increased by quite a lot. I suspect this is because the database has over a hundred tables and it's compiling and getting data from all of them as opposed to just the two I need. Is there a way to restrict the EntityTypeProvider to only referencing the needed tables in the schema?
type private EntityConnection = SqlEntityConnection<ConnectionString="Server=Server;Initial Catalog=Database;Integrated Security=SSPI;MultipleActiveResultSets=true", Pluralize = true>
let private context = EntityConnection.GetDataContext()
I have not tried this myself, but I think you could add a new "ADO.NET Entity Data Model" (edmx) file to your project, let it generate from your existing database, and then delete from the model every table you don't want accessible to your code.
The EDMX designer will generate a *.csdl file that you can then reference from the LocalSchemaFile parameter of SqlEntityConnection. You'd use this parameter instead of ConnectionString.
The end result is that the entity provider would not automatically pick up changes to your database, but compilation times will go down, and only the tables you care about would be visible to your code.
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.