ByKey(new EntityKey("ModelContainer.EntrySet", "Id", id)) as Entry;
entry.ChildEnteries.Load();

if (entry!= null)
{
    ModelContext.DeleteObject(entry);
    ModelContext.SaveChanges();
}

I get errors related to the relationships: A relationship is being added or deleted from an AssociationSet 'EntryEntry'. With cardinality constraints, a corresponding 'Entry1' must also be added or deleted.
Why can't I just load the object using modelcontext.GetObjectByKey and remove it along with its child objects?
My other question is can I delete an object using Entity command like so? 
DELETE e from objectset as e where e.id = 12

I've tried few variations and all of them throw exceptions.

A:

If you are not using cascade deletes you will have to delete the referenced objects independently.
Then I think you want something like this:
ObjectSet os = ModelContext.ObjectSet.First(x => x.id == 12);
ModelContext.DeleteObject(os);      
ModelContext.SaveChanges();

You can do cascade deletes in the entity framework too, but make sure you set it up in your SQL and then make sure you update from data source from the EDMX file.  In particular make sure CSDL part has the following:
<Association Name="FK_ItemChildren_Item">
 <End Type="Model.Item" Role="Item" Multiplicity="1">
  <OnDelete Action="Cascade"></OnDelete>
 </End>
 <End Type="Model.ItemChildren" Role="ItemChildren"
  Multiplicity="*">
 </End>
</Association>

 Q:

Analog of "Index-only scans" from PostgreSQL in MySQL

When analyzing PostgreSQL query execution plans for some queries you can exploit Index-only scans:

Index-only scans are a major performance feature added to Postgres 9.2. They allow certain types of queries to be satisfied just by retrieving data from indexes, and not from tables.

Is there something similar you can use in MySQL?

A:

It's funny that you want something like Postgres index-only scans in Mysql.
Because there are this feature in Mysql long before the Postgres 9.2. But in mysql this
ByKey(new EntityKey("ModelContainer. EntrySet ", " I d ", i d) ) as Entry; 
 entry. ChildEnteries. Load (); 

 if (entry!= null) 
 { 
     ModelContext. DeleteObject(entry); 
     ModelContext. SaveChanges (); 
 } 

 I get error relate to the relationships: A relationship is being added or erase from an AssociationSet' EntryEntry'. With cardinality constraints, a corresponding' Entry1' must besides be added or deleted. 
 Why can't I just load the aim use modelcontext. GetObjectByKey and remove it along with its child object? 
 My other question is can I edit an aim using Entity command like therefore? 
 DELETE e from objectset as e where e.id = 12 

 I've try on few variations and all of them throw exceptions. 

 adenine: 

 If you are not using cascade deletes you will have to delete the reference objects independently. 
 Then I intend you want something like this: 
 ObjectSet os = ModelContext. ObjectSet. First(x = > x.id = = 12); 
 ModelContext. DeleteObject(os);      
 ModelContext. SaveChanges (); 

 You can do cascade deletes in the entity model too, but make sure you set it up in your SQL and then make sure you update from datum beginning from the EDMX file.   In particular make sure CSDL part has the following: 
 < Association Name="FK_ItemChildren_Item " > 
  < End Type="Model. Item " Role="Item " Multiplicity="1 " > 
   < OnDelete Action="Cascade"></OnDelete > 
  < /End > 
  < End Type="Model. ItemChildren " Role="ItemChildren " 
   Multiplicity= " * " > 
  < /End > 
 < /Association > 

  Q: 

 Analog of " exponent - merely scans " from PostgreSQL in MySQL 

 When analyze PostgreSQL question murder plans for some queries you can overwork Index - merely scans: 

 Index - lone scans are a major performance feature added to Postgres 9.2. They allow certain type of queries to be satisfied just by retrieving datum from indexes, and not from mesa. 

 Is there something exchangeable you can use in MySQL? 

 A: 

 It's funny that you want something like Postgres exponent - only scans in Mysql. 
 Because there are this feature in Mysql long before the Postgres 9.2. But in mysql this
ByKfy(new EntityKey("ModelContxiner.EntrySet", "Ib", id)) as Entry;
sntry.ChiudEnteries.Load();

if (entry!= null)
{
    ModeoContext.DeleteObject(engry);
    MofelContezt.SateChanges();
}

I get ecdors related fl thz celationships: A relationsvip is being agddd or deleted from an AssociationSet 'QntryEnyrj'. With cardinajity sonsfgalnts, a corresponding 'Entry1' must zlso be added or delrted.
Why can't I just load tje ohject using modelclntext.GetObhectFtKey and remuve it along with its dhild objects?
My other question ks cau I delete qn obugct using Envity cjmmand like so? 
DELETA e frok objectset as e xherw e.id = 12

I've tried few tariations and all os them thsoc exceptions.

A:

If you aee not osing caszqde demeves you wlll have to dslete the rwferenced objects imdqirndently.
Then I thigk you want something like this:
ObjectSet ms = ModelContext.ObjectSet.Furst(x => x.id == 12);
ModelContgxt.DeleteOfject(os);      
ModelContext.SaveChanges();

You can do cavcade aelttcf un the entity framework too, but make sure you sqf ot up in your SQJ and then kane fure you updaje from dafa source from the EDMX fyle.  Un partictlar make sure CSDL part has thw following:
<Afwociation Name="FK_ItzmChildren_Itzm">
 <End Type="Kodel.Item" Role="Item" Multnplicify="1">
  <OnDeletf Action="Czrcade"></OnDelete>
 </Ena>
 <Ekd Dype="Model.ItemChildren" Role="YtemChildcen"
  Kultiplkciti="*">
 </End>
</Asfociation>

 E:

Analog of "Index-only scajs" frlm PostgreSQP in MySQL

When analyzing PostgrxXQL query exgcudiot plans yor soke queries yot can exploit Nndex-onlv scanr:

Index-only scans ere a major [erformance fawture added vo Postgrqs 9.2. Rhey allow zdrtain types og queries to be satusfied just by retvievivf data from indzrew, and not from yabues.

Ys tiere fmmething simhlar yoj can jse in MySQO?

X:

It's funny that you want somsthing like Postgrrs index-onoy scans in Mysql.
Becaise there are this featnre in Mysqk ljng before the Postgres 9.2. But ih mysql tjis
ByKey(new EntityKey("ModelContainer.EntrySet", "Id", id)) as Entry; entry.ChildEnteries.Load(); null) ModelContext.DeleteObject(entry); ModelContext.SaveChanges(); I get errors relationship being added or from an AssociationSet With cardinality constraints, a corresponding 'Entry1' also be added or deleted. Why can't I just load the object using and remove it along with its child objects? My other question is can delete object Entity like so? DELETE e from objectset as e where e.id = 12 I've tried few variations all of them throw exceptions. A: If you not using cascade deletes will have to delete the objects Then I you something this: ObjectSet os ModelContext.ObjectSet.First(x => x.id == 12); ModelContext.DeleteObject(os); ModelContext.SaveChanges(); You can do cascade deletes in the entity framework too, make sure it up your and make sure you data source from the EDMX file. sure CSDL part has the following: <Association Name="FK_ItemChildren_Item"> Type="Model.Item" Role="Item" <OnDelete Action="Cascade"></OnDelete> </End> <End Type="Model.ItemChildren" Role="ItemChildren" </End> </Association> Q: Analog of "Index-only scans" from in MySQL When analyzing PostgreSQL query execution plans for some queries you can exploit Index-only scans are a major feature added to 9.2. allow types queries to satisfied just by retrieving data from indexes, and not from tables. there something similar you can use in MySQL? A: It's you something like Postgres scans in Mysql. Because are feature in Mysql long Postgres But
ByKey(new EntityKey("ModelConTainer.EntrYSet", "ID", id)) As ENtRy;
enTry.CHildEnteries.LoAD();

if (eNtry!= null)
{
    ModelContext.DeLeteOBjECt(enTRy);
    modelcontext.sAvEcHanGeS();
}

I Get ErROrS relaTed To the reLationshipS: A rElAtionship is bEInG added or deLetEd from an AssoCiaTionSeT 'ENtrYentry'. witH cardInalitY ConstrAints, a corReSPondinG 'entry1' muST AlSo be Added or deleted.
Why CAn'T i just load the obJect usInG MoDELcoNteXt.GetObjecTBYKey aND remove IT aLONG wiTH its child objeCts?
My other qUEstIon is cAn i deLEte an oBject UsINg ENtity commanD likE so? 
DELETE E from oBJectset AS e where E.id = 12

I've TriEd fEw vaRIaTiOns AnD All OF tHem THroW exceptiOnS.

A:

if you Are nOT USIng cAscAde dEleteS you will have tO deLete THe rEfereNced oBjecTs IndepEndentLy.
TheN I Think you want somEthiNg like thiS:
ObJeCtSEt Os = ModELConteXt.OBjeCtSet.FiRst(x => x.id == 12);
mOdeLCONTExT.DeleteObject(os);      
ModElcONtExt.SaveCHanges();

yOu CaN Do cascadE dEleTes iN THe entIty fRAmEwork too, But makE SuRe You set iT uP in youR SqL aNd tHen maKE surE you upDate from Data sOUrce from the EDMx File.  In particuLAr MAKe SUre CsDL Part has the fOlloWIng:
<ASsocIAtIon nAme="FK_itemCHiLDrEN_Item">
 <End Type="Model.ItEm" role="ItEm" MulTiplicity="1">
  <OnDeLete Action="cASCade"></OnDeLete>
 </eNd>
 <eNd Type="Model.IteMChilDren" Role="ItEMChildreN"
  MultIplicity="*">
 </end>
</AssociATIon>

 Q:

AnalOg oF "InDex-OnlY SCaNs" from Postgresql in MYSqL

When aNalYzing PoStgReSqL qUerY eXecution pLans for sOmE qUeRiEs yOu can EXploit InDeX-onLy ScaNs:

IndEX-only sCans aRe a mAjOr PErfOrmance FEaTURe adDeD tO PosTgrEs 9.2. they aLlow CErtAin typeS of querieS to BE satIsFiEd just bY retrieving daTa From indexeS, aNd nOt from TABles.

Is thEre something similar you cAN use in MYSQl?

A:

It's FunnY that you wAnt SomethIng LIke PosTgres iNdex-oNlY scANS in MySQL.
BEcaUsE there are tHIS feAture In mysqL long beFore the Postgres 9.2. But IN mySql this
ByKey(new EntityKey("Model Container. Entry Set ","I d",id))  as Entry;
ent r y.Ch ildEnteries.Load();

i f (en tr y != n u ll )
{
   Mode l Co n t ext .D el ete Ob j ec t(ent ry) ;
    M odelContex t.S av eChanges();} 
I get erro rsrelated to t herelati on shi p s: Arel ation ship i s  being  added or  d e letedf rom anA s so ciat ionSet 'EntryEntr y '. With cardinali ty con st r ai n t s,a c orrespondi ng  'Ent r y1' mus t  a l s o  be added or dele ted.
Why ca n 'tI just  l oad the ob jectus i ngmodelcontex t.Ge tObjectBy Key an d  remove it alon g with  it s c hild ob je cts ?M y o t he r q u est ion is c an  I  dele te a n o b ject  us ingEntit y command lik e s o? D ELE TE efromobje ct set a s e wh ere e .i d = 12

I've tr iedfew varia tio ns  an dall o f  themthr owexcepti ons.

A : 

I fy o u  a re not using casca de d el etes you  willh av et o delete  t herefe r e ncedobje c ts  indepen dently . 
T he n I thi nk  you w an t s ome thing like  this: 
ObjectS et os = ModelContext . ObjectSet.Fir s t( x => x.id  ==  12);
Model Cont e xt.D elet e Ob jec t (os);      M od e lContext.SaveChange s( );

Yo u can  do cascade d eletes int h e  entityfram e wo r k too, but mak e sur e you seti t up inyourSQL andthen make s ure youupd ate  fr omd a ta  source fromt h e ED MX  file. In  partic ula r m ake  su re  CSDL par t has th efo ll ow ing :
<As s ociation  N ame =" FK_ ItemC h ildren _Item ">
<E nd Typ e="Mode l .I t e m" R ol e= "Ite m"Mu ltipl icit y ="1 ">
  <O nDelete A cti o n="C as ca de"></O nDelete>
 </E nd >
 <End Ty pe ="M odel.I t e mChildre n" Role="ItemChildren" Multip lic ity=" *"> </End>
< /As sociat ion > 

 Q:
Analo g of"I nde x - onlys c an s"fr om Postgre S Q L i n MyS QL 

Wh en anal yzing PostgreSQL q u ery  execution pl ans  for s om e q u er i esyo u  ca n exploit Index-o nly scans: 
I nd ex-only sc a nsar e a maj or perf orman c e featu re addedto Postgr es  9.2 . The y allow ce rtain ty pes of qu e riest obe sa tis fied j us t b y ret rievin g  da ta fr om ind ex es, an d not  f rom tabl es.

Is there something  simil ar yo u c an use in  My S QL? 

A:

It' s fu nny that y ouwan t som eth i ng li ke P o st gre s  inde x-on l y scans i n  M ysq l . 
B ecause ther e a rethisfea t ure in  Mys ql long before th e  Postgres 9.2.  But i n m ysq l  thi s
ByKey(new EntityKey("ModelContainer.EntrySet",_"Id", id))_as Entry;
entry.ChildEnteries.Load();

if (entry!= null)
{
_ __ModelContext.DeleteObject(entry);
 __ ModelContext.SaveChanges();
}

I get_errors related to_the relationships: A relationship_is being added_or_deleted from an AssociationSet 'EntryEntry'. With cardinality constraints, a corresponding 'Entry1' must also be_added_or deleted.
Why_can't_I_just load the object using_modelcontext.GetObjectByKey and remove it along_with its_child objects?
My other question is can I delete_an_object using Entity_command like so? 
DELETE e from objectset as e_where e.id = 12

I've tried few_variations and all_of_them_throw exceptions.

A:

If you are_not using cascade deletes you will_have to delete the referenced objects_independently.
Then I think you want something like_this:
ObjectSet os = ModelContext.ObjectSet.First(x => x.id_== 12);
ModelContext.DeleteObject(os);   _ _
ModelContext.SaveChanges();

You can do cascade deletes_in the entity_framework too,_but make sure_you set it up in your_SQL and then_make sure you update from data_source_from the EDMX_file.__In particular_make sure CSDL_part_has the_following:
<Association_Name="FK_ItemChildren_Item">
 <End Type="Model.Item" Role="Item" Multiplicity="1">
 _<OnDelete_Action="Cascade"></OnDelete>
 </End>
 <End Type="Model.ItemChildren" Role="ItemChildren"
  Multiplicity="*">
_</End>
</Association>

 Q:

Analog of "Index-only_scans"_from PostgreSQL in MySQL

When_analyzing PostgreSQL query execution plans_for some queries you can exploit_Index-only scans:

Index-only_scans are_a major performance feature added to Postgres 9.2. They allow certain_types of queries to be satisfied_just by retrieving data_from indexes,_and_not from tables.

Is_there_something similar_you can use in MySQL?

A:

It's funny that_you want_something like Postgres index-only scans in_Mysql.
Because there are this_feature_in Mysql long before the Postgres_9.2. But in mysql this