CODEWITHSUNDEEP
c#nhibernatemapping
zayden
zayden

Reputation: 57

NHibernate Map an Object without a table

I'm trying to map the following object:

public class DatabaseInfo
{
    public virtual DateTime CurrentDateTime { get; set; }
}

with the following map:

public class DatabaseInfoMap : ClassMapping<DatabaseInfo>
{
    public DatabaseInfoMap()
    {
        Property(x => x.CurrentDateTime, map => { map.Formula("(SELECT CURRENT UTC TIMESTAMP AS CurrentDateTime)"); });
    }
}

I am getting a validation error, as the Map does not contain a 'Table' definition. Is it not possible to map obejcts without having to make a Table or View?

I'm not sure if this is the right approach for me to get the database time via NHibernate. Any help is appreciated.

Upvotes: 0

Views: 77

Answers (2)

Firo
Firo

Reputation: 30813

Since there is no table mapping as an entity makes no sense (no identity). I suggest:

public class DatabaseInfo
{
    public static DatabaseInfo Get(ISession session)
    {
        return session.CreateSQLQuery("SELECT CURRENT UTC TIMESTAMP AS CurrentDateTime").SetResultTransformer(Transformers.AliasToBean<DatabaseInfo>()).UniqueResult<DatabaseInfo>();
    }

    public DateTime CurrentDateTime { get; protected set; }
}

Upvotes: 1

David Osborne
David Osborne

Reputation: 6821

Can't you just use:

public class DatabaseInfo
{
    public DateTime CurrentDateTime { get; set; } = DateTime.UtcNow;
}

When NH hydrates your object, or a graph containing this object, this property will be set with that default value.

Upvotes: 0

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