覆盖长文本字符串的流畅 NHibernate nvarchar(MAX) 而不是 nvarchar(255)

问题描述

当您在 fluent NHibernate 中设置字符串值时，它总是将 DB 值设置为 Nvarchar(255)，我需要存储相当多的基于用户输入的长字符串，而 255 是不切实际的.

补充一点，这是自动映射器的一个问题，因为我正在使用流畅的 NHibernate 来构建数据库.

解决方案

添加此约定会将字符串属性的默认长度设置为 10000.正如其他人所指出的，这将是一个 nvarchar(max) 列.

public class StringColumnLengthConvention : IPropertyConvention, IPropertyConventionAcceptance{public void Accept(IAcceptanceCriteriacriteria){标准.期望(x => x.Type == typeof(string)).Expect(x => x.Length == 0);}公共无效应用(IPropertyInstance 实例){实例长度(10000)；}}

可以像这样将约定添加到自动映射配置中:

Fluently.Configure().Mappings(m =>m.AutoMappings.Add( AutoMap.AssemblyOf().Conventions.Add()))

有关详细信息，请参阅 Fluent NHibernate wiki 中的约定.>

When ever you set a string value in fluent NHibernate it alwasy sets the DB vales to Nvarchar(255), I need to store quite a lot of long string which are based on user inputs and 255 is impractical.

Just to add this is an issue with the automapper as I am using fluent NHibernate to build the database.

解决方案

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 be added to an automap configuration like this:

Fluently.Configure()
    .Mappings( m =>
        m.AutoMappings.Add( AutoMap.AssemblyOf<Foo>()
        .Conventions.Add<StringColumnLengthConvention >()))

For more information, see Conventions in the Fluent NHibernate wiki.

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