HasOne creates a one-to-one mapping between tables for you. References creates a typical relational many-to-one relationship. More defined: a one-to-one relationship means that when one record exists in one table, it must (or can) have one and at most one record in the other referenced table. Example: User table and Options table (one user has … Read more
You can just use SchemaUpdate instead, it will update the schema if it exists and create it if it does not: public NhibernateSessionFactory(IPersistenceConfigurer config) { _sessionFactory = Fluently.Configure(). Database(config). Mappings(m => m.FluentMappings.AddFromAssemblyOf<MappingsPersistenceModel>()). ExposeConfiguration(cfg => new SchemaUpdate(cfg).Execute(false, true)). BuildSessionFactory(); } One caveat: SchemaUpdate does not do destructive updates (dropping tables, columns, etc.). It will only add … Read more
Adding this convention will set the default length for string properties to 10000. As others have noted, this will be a nvarchar(max) column. public class StringColumnLengthConvention : IPropertyConvention, IPropertyConventionAcceptance { public void Accept(IAcceptanceCriteria<IPropertyInspector> criteria) { criteria.Expect(x => x.Type == typeof(string)).Expect(x => x.Length == 0); } public void Apply(IPropertyInstance instance) { instance.Length(10000); } } Conventions can … Read more
There’s a CompositeId method. public class EntityMap : ClassMap<Entity> { public EntityMap() { CompositeId() .KeyProperty(x => x.Something) .KeyReference(x => x.SomethingElse); } }
This is a well known issue with NHibernate handling nvarchar(max), see : http://geekswithblogs.net/lszk/archive/2011/07/11/nhibernatemapping-a-string-field-as-nvarcharmax-in-sql-server-using.aspx For some years now, I have been file mapping nvarchar(max) columns to StringClob without encountering any problem : <property name=”myProp” column=”MY_PROP” not-null=”true” type=”StringClob” access=”property”></property> This link (from the comments) describes the fluent mapping required to fix this issue: https://www.tritac.com/nl/blog/fluent-nhibernate-nvarchar-max-fields-truncated-to-4000-characters/ Map(x => x.Description).CustomType(“StringClob”).CustomSqlType(“nvarchar(max)”);
To get a bidirectional association with a not-null foreign key column in the Details table you can add the suggested Owner property, a References(…).CanNotBeNull() mapping in the DetailsMap class, and make the Summary end inverse. To avoid having two different foreign key columns for the two association directions, you can either specify the column names … Read more
I can see from forum and blog posts everywhere that lots of others before me have looked for a way to get the SQL statements as they’re being prepared for execution. The answer typically is something along the lines of “you can’t”, or “you shouldn’t”. Whether I should or not, that’s what I wanted. After … Read more
The SchemaUpdate object provides database schema updating, by apparently generating and executing a series of SQL UPDATE statements (as well as constraint statements) when it’s void Execute(bool script, bool doUpdate) function is called. The SchemaUpdate class is in the NHibernate.Tool.hbm2ddl namespace, which can be found in the Nhibernate.dll file. SchemaUpdate is mentioned in chapter 15 … Read more
You can get the generated sql queries without execution with the following methods: For the NHibernate.Linq queries: public String GetGeneratedSql(System.Linq.IQueryable queryable, ISession session) { var sessionImp = (ISessionImplementor) session; var nhLinqExpression = new NhLinqExpression(queryable.Expression, sessionImp.Factory); var translatorFactory = new ASTQueryTranslatorFactory(); var translators = translatorFactory.CreateQueryTranslators(nhLinqExpression, null, false, sessionImp.EnabledFilters, sessionImp.Factory); return translators[0].SQLString; } For Criteria queries: public … Read more
Use collection interfaces instead of concrete collections, so NHibernate can inject it with its own collection implementation. In this case, use IList<int> instead of List<int>