iphone - Core data with to-many relationship/ -
i using core data. having 2 entities music , lyrics .i created relationship musictolyrics inverse , to-many. have save number of timestamps , lyrics 1 song. m using code
lyrics *lyrics = [nsentitydescription insertnewobjectforentityforname:@"lyrics" inmanagedobjectcontext:context]; lyrics.lyrics = albumtitlefield.text; lyrics.starttime = 0.0; lyrics.lyricstomusic = music;
this saving in coredata. want save number of records 1 song..just foreign key.. how can ? please help.
thanks in advance
it looks inverse wrong way. rather "music" quite ambiguous, let's call "song". so, song
has "lyrics". other songs use same lyrics
.
so far then, have many-to-one relationship in many songs can use same lyrics.
what i'd recommend map out in core data modeller. then, generate class files automatically. you'll see in to-many relationship, can add object set, you'll have example:
song *mysong = [nsentitydescription insertnewobjectforentityforname:@"song" innmanagedobjectcontext:context]; lyrics *mylyrics = [nsentitydescription insertnewobjectforentityforname:@"lyrics" innmanagedobjectcontext:context];
that's 2 objects in core data. define relationship inverse:
song.lyrics = mylyrics; [mylyrics addsongobject:mysong];
if set things correctly in model, you'll see method addsongobject
generated automatically.
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