This is a pretty easy one to solve. This happens because the column attribute in the mapping file does not exist on the database being accessed. <property name=”SpelledWrong” column=”SPELLDWRONG” type=”string” /> More than likely there is a spelling mistake or the column doesn’t exist on the table being mapped.
Read More →In all of my NHibernate implementations I serialize the startup. It saves a noticeable amount of time. We know that without it, NHibernate validates all the mapping files each time we start the program. If we only have 1 or 2 simple files it is not a problem, however, if you have a large implementation, […]
Read More →The following error is generally caused when there is a misspelling or case miss match between the class file and the mapping file. Review the contents of both and confirm spelling and case are the same so that the ‘Could not compile the mapping document: hbm.xml’ error can be avoided. The inner exception is something […]
Read More →The equivalent to LIKE via the LINQ to NHibernate provider is Contains. An example of a LINQ to NHibernate that will return a result set matching a search like parameter is below. IQueryable<Classname> linqLIKE = (from m in session.Query<Classname>() where m.Code.Contains(“%dex%”) orderby m.CreateDate select m); IList<Classname> ListLIKE = linqLIKE.ToList(); The above […]
Read More →Firstly, let me say that there is nothing special about this upgrade. The instructions which I wrote here will still work with an 11g database. The issue I had was more with, what is the difference between a SID and a SERVICE_NAME which is used to identify the data instance to connection to. The SID […]
Read More →I was working on a system which had implemented NHibernate, primarily for its ability to support multiple DBMS, such as Oracle and MS SQL Server. The problem came up when trying to insert, specifically in regards to the ID data type. On Oracle the ID data type was NHUMBER, while on MS SQL Server the […]
Read More →In continuation of a previous blog which compared 2 simple SELECT statements between NHibernate and Entity Framework, I do the same with the joining of 2 tables together. NHibernate Figure 1 shows the LINQ to NHibernate query which selects all the data from the PostForNHibernate table, joins with the BlogForNHibernate table using the foreign key […]
Read More →Sometime things don’t always go as planned. I was making some nice progress with the process of mapping a database and all of a sudden I get the following compile time error message. Ambiguous type reference. A type named “Attribute” occurs in at least two namespaces. “Attribute” ist ein mehrdeutiger Verweis und kann “System.Attribute” oder […]
Read More →If you receive this error then you have probably mixed up some data types between your class (class.cs) file and your mapping (class.hbm.xlm) file. For example you have a property defined in your class file as a string and then in your mapping file as an int. To repair the PropertyAccessException Invalid Cast (check your […]
Read More →Common sense, maybe…, worthy of a blog, absolutely. I was creating an ordering system using NHibernate and the table which stored the orders was called ORDER. This resulted in an error, which I believe would come from any data retrieval source, I just happen to be using NHibernate with SQL Server and Oracle. The error […]
Read More →