c# - Which algorithm to use with many-to-many relation in NHibernate -


I have many-to-many relationships between photos and tags: a photo can have multiple tags and many photos Can I share the same tag

I have a loop that scans photos in a directory and then adds them to NHibernate. Some tags are added to photos during that process, eg. A 2009-tag when taken in photo 200 9.

An equally and gatehashcode is applied in the tag category and uses the name property as a signature property only. Both photos and tags are the key to rent and versions.

I have some code like the following: 

  Public Zero Import () {... foreach (var fileName fileNames) {var photo = new photo {FileName = FileName}; AddDefaultTags (_session, photo, fileName); _session.Save (photo); } ...} Add Private Zero AddDefaultTags (...) {... var tag = _session.CreateCriteria (typeof (tag)). (Restriction "." ("Name", year.ToString ()). Unicrus result & lt; Tag & gt; (); If (tag! = Null) {photo.AddTag (tag); } Else {var tag = new tag {name = year.ToString ())}; _session.Save (tag); Photo.AddTag (tag); }}

My problem occurs when the tag does not exist, e.g. The first picture of a new year. The addDefaultTags method checks that the tag exists in the database and then creates it and connects to NHibernate. It works very well in adding a picture, but when importing many photos in the new year and the same unit of work Within, this fails because it is still not present in the database and it has been added again. This fails when completing the work unit because it tries to add two entries in the tag table with the same name ...

My question is, there are ways to ensure that NHibernate tries to create only one tag Databases in the above situation Do I need to retain the list of newly added tags or can I set the mapping in such a way that it works?

You need to run _session.Flush () if your criteria Should not return the forced data or you should be able to do this correctly by setting _session.FlushMode

with FlushMode.Auto, before the criteria are executed The session will be automatically shot.

EDIT: And important! When you read the code shown, it does not appear that you are using the transaction for the unit of your work. I advise to wrap my unit of work in the transaction - if you have NH 2.0 +! If you are using Flushmode to work, Auto is required!

Read more here:


Comments

Post a Comment

Popular posts from this blog

python - Overriding the save method in Django ModelForm -

I'm having trouble overriding a ModelForm save method. I get this error I'm: Exception type: TypeErier Exception Value: Save () found an unexpected keyword argument 'committed' My intentions include a form 3 fields Submit several values ​​for, then create an object for each combination of those areas, and to save each object file models.py class collarsult type (models.Model): id = model. AutoField (db_column = 'icontact_result_code_type_id', primary_key = true) callResult = models.ForeignKey ( 'CallResult', db_column = 'icontact_result_code_id') campaign = models.ForeignKey ( 'campaign', db_column = 'icampaign_id') CALLTYPE = models.ForeignKey ( 'CALLTYPE', db_column = 'icall_type_id') agent = models.BooleanField (db_column = 'bagent', default = true) teamLeader = models.BooleanField (db_column = 'bTeamLeader', default = true) active = models.BooleanField (db_column = Django.form...
Read more

html - CSS autoheight, but fit content to height of div -

I have a div in which there are three children- div in the left and middle div: float: left while true: float: true because it is my layout Actually will spoil, I've used ClearFix Hack: .cf {zoom: 1; }. Cf: First,. Cf: {content: ""; Display: Table; }. Cf: After {clear: both; } It still works, but I want to be the right div an indicator. So it should fill 100% of the parent unit of height. How can I complete this? PS is the full code: & Lt; / Div & gt; & Lt; Div class = "mobile_content" & gt; & Lt; H5 & gt; {{Data.titel}} & lt; / H5> & Lt; Table & gt; & Lt; TR & gt; & Lt; Th & gt; Komponist: & lt; / Th & gt; & Lt; TD & gt; {{Data.komponist}} & lt; / TD & gt; & Lt; / TR & gt; & Lt; TR & gt; & Lt; Th & gt; Instrument: & lt; / Th & gt; & Lt; TD & gt; {{Data.instrumente}} & lt; / TD & gt; & Lt; / TR & gt;...
Read more

qt - How to prevent QAudioInput from automatically boosting the master volume to 100%? -

I have been trying to use Qt5 multimedia to record audio with QAudioInput, however, when I see If QAudioInput is started, it increases the master volume of my sound device to 100%. How can I prevent QAudioInput from changing the master volume? My current development platform is Linux with PalsAdio (with flat audio disabled). How can I use QAudioInput : QAudioDeviceInfo device_info = QAudioDeviceInfo :: defaultInputDevice (); QAudio format format; Format.setSampleRate (44100); Format.setChannelCount (1); Format.setSampleSize (16); Format.setCodec ("Audio / PCM"); Format.setSampleType (QAudioFormat :: SignedInt); Format.setByteOrder (QAudioFormat :: LittleEndian); Std :: cout & lt; & Lt; Device_info.deviceName (). ToUtf8 (). ConstData () & lt; & Lt; Std :: endl; QAudioInput * default_device = new QAudioInput (device_info, format); QIODevice * default_io_device = default_device-> Start (); a QAudioInput.setVolume () method is not you I ...
Read more