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What's the better way to implement a condition at NHibernate query?

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1

2

I am using a generics implementation of Query from NHibernate.

My method:

public IEnumerable<TEntidade> ObterEntidadesPor(Func<TEntidade, bool> where)
 
 return SessionNH.Query<TEntidade>().Where(where);
 

In this case, the NHibernate first do the "select * from TEntidade" bring all information to memory after all this, he implement the "where" conditional. This are taking to much time.

Is there a better way to do it?

c# nhibernate orm

share|improve this question

asked Mar 27 at 13:22

Aness Ollem AzuosAness Ollem Azuos

3811 silver badge99 bronze badges

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  why not use Entity Framework, (not sure about NHibernate) but EF translates where to WHERE clause in SQL and doesn't pull all records in memory to do filtering.
  
  – Aarif
  Mar 27 at 13:26
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  All applications here are using NHibernate. I can't change to EF without a big impact.
  
  – Aness Ollem Azuos
  Mar 27 at 13:34
  
  

  
  
  
  


• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  
  Try with Expression<Func<TEntidade, bool>> where instead
  
  – Roman Artiukhin
  Mar 27 at 16:06
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  That's it! The Expression<Func<TEntidade, bool>> where work it. Thanks!
  
  – Aness Ollem Azuos
  Mar 27 at 18:01
  

  
  
  
  

add a comment | 

1

2

I am using a generics implementation of Query from NHibernate.

My method:

public IEnumerable<TEntidade> ObterEntidadesPor(Func<TEntidade, bool> where)
 
 return SessionNH.Query<TEntidade>().Where(where);
 

In this case, the NHibernate first do the "select * from TEntidade" bring all information to memory after all this, he implement the "where" conditional. This are taking to much time.

Is there a better way to do it?

c# nhibernate orm

share|improve this question

asked Mar 27 at 13:22

Aness Ollem AzuosAness Ollem Azuos

3811 silver badge99 bronze badges

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  why not use Entity Framework, (not sure about NHibernate) but EF translates where to WHERE clause in SQL and doesn't pull all records in memory to do filtering.
  
  – Aarif
  Mar 27 at 13:26
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  All applications here are using NHibernate. I can't change to EF without a big impact.
  
  – Aness Ollem Azuos
  Mar 27 at 13:34
  
  

  
  
  
  


• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  
  Try with Expression<Func<TEntidade, bool>> where instead
  
  – Roman Artiukhin
  Mar 27 at 16:06
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  That's it! The Expression<Func<TEntidade, bool>> where work it. Thanks!
  
  – Aness Ollem Azuos
  Mar 27 at 18:01
  

  
  
  
  

add a comment | 

I am using a generics implementation of Query from NHibernate.

My method:

public IEnumerable<TEntidade> ObterEntidadesPor(Func<TEntidade, bool> where)
 
 return SessionNH.Query<TEntidade>().Where(where);
 

In this case, the NHibernate first do the "select * from TEntidade" bring all information to memory after all this, he implement the "where" conditional. This are taking to much time.

Is there a better way to do it?

c# nhibernate orm

share|improve this question

asked Mar 27 at 13:22

Aness Ollem AzuosAness Ollem Azuos

3811 silver badge99 bronze badges

share|improve this question

asked Mar 27 at 13:22

Aness Ollem AzuosAness Ollem Azuos

3811 silver badge99 bronze badges

share|improve this question

asked Mar 27 at 13:22

Aness Ollem AzuosAness Ollem Azuos

3811 silver badge99 bronze badges

asked Mar 27 at 13:22

Aness Ollem AzuosAness Ollem Azuos

3811 silver badge99 bronze badges

asked Mar 27 at 13:22

Aness Ollem AzuosAness Ollem Azuos

3811 silver badge99 bronze badges

1 Answer
1

active

oldest

votes

0

The problem was solved with Expression<func>.

public IEnumerable<TEntidade> ObterEntidadesPor(Expression<Func<TEntidade, bool>> where)

 return SessionNH.Query<TEntidade>().Where(where);

While searching for answer, a colleague told me that the Func executes the query before build an expression. To build an expression before executing the query, we have to use Expression.

This is also mentioned by @RomanArtiukhin in comments on question.

share|improve this answer

edited Mar 28 at 7:09

Amit Joshi

7,78377 gold badges3333 silver badges7272 bronze badges

answered Mar 27 at 18:05

Aness Ollem AzuosAness Ollem Azuos

3811 silver badge99 bronze badges

add a comment | 

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0

The problem was solved with Expression<func>.

public IEnumerable<TEntidade> ObterEntidadesPor(Expression<Func<TEntidade, bool>> where)

 return SessionNH.Query<TEntidade>().Where(where);

While searching for answer, a colleague told me that the Func executes the query before build an expression. To build an expression before executing the query, we have to use Expression.

This is also mentioned by @RomanArtiukhin in comments on question.

share|improve this answer

edited Mar 28 at 7:09

Amit Joshi

7,78377 gold badges3333 silver badges7272 bronze badges

answered Mar 27 at 18:05

Aness Ollem AzuosAness Ollem Azuos

3811 silver badge99 bronze badges

add a comment | 

0

The problem was solved with Expression<func>.

public IEnumerable<TEntidade> ObterEntidadesPor(Expression<Func<TEntidade, bool>> where)

 return SessionNH.Query<TEntidade>().Where(where);

While searching for answer, a colleague told me that the Func executes the query before build an expression. To build an expression before executing the query, we have to use Expression.

This is also mentioned by @RomanArtiukhin in comments on question.

share|improve this answer

edited Mar 28 at 7:09

Amit Joshi

7,78377 gold badges3333 silver badges7272 bronze badges

answered Mar 27 at 18:05

Aness Ollem AzuosAness Ollem Azuos

3811 silver badge99 bronze badges

add a comment | 

The problem was solved with Expression<func>.

public IEnumerable<TEntidade> ObterEntidadesPor(Expression<Func<TEntidade, bool>> where)

 return SessionNH.Query<TEntidade>().Where(where);

While searching for answer, a colleague told me that the Func executes the query before build an expression. To build an expression before executing the query, we have to use Expression.

This is also mentioned by @RomanArtiukhin in comments on question.

share|improve this answer

edited Mar 28 at 7:09

Amit Joshi

7,78377 gold badges3333 silver badges7272 bronze badges

answered Mar 27 at 18:05

Aness Ollem AzuosAness Ollem Azuos

3811 silver badge99 bronze badges

public IEnumerable<TEntidade> ObterEntidadesPor(Expression<Func<TEntidade, bool>> where)

 return SessionNH.Query<TEntidade>().Where(where);

share|improve this answer

edited Mar 28 at 7:09

Amit Joshi

7,78377 gold badges3333 silver badges7272 bronze badges

answered Mar 27 at 18:05

Aness Ollem AzuosAness Ollem Azuos

3811 silver badge99 bronze badges

edited Mar 28 at 7:09

Amit Joshi

7,78377 gold badges3333 silver badges7272 bronze badges

edited Mar 28 at 7:09

Amit Joshi

7,78377 gold badges3333 silver badges7272 bronze badges

answered Mar 27 at 18:05

Aness Ollem AzuosAness Ollem Azuos

3811 silver badge99 bronze badges

answered Mar 27 at 18:05

Aness Ollem AzuosAness Ollem Azuos

3811 silver badge99 bronze badges