php - What does exclusive option in hasMany? -


in cakephp, there option called "exclusive" in "hasmany" field in models. documentation says:

when exclusive set true, recursive model deletion delete deleteall() call, instead of deleting each entity separately. improves performance, may not ideal circumstances.

but not clear. want know option exactly, , happens if don't use it? thanks.

say example, 1 author has many books.so can write in form of $hasmany association below,

   var $name = 'author';        var $hasmany = array('book' =>         array('classname' => 'book',             'conditions' => '',             'foreignkey' => 'author_id',             'dependent' => true,             'exclusive' => true          )     );

dependent: when dependent set true, recursive model deletion possible. in example, book records deleted when associated author record has been deleted.

exclusive – if set true, associated objects deleted in 1 sql statement without having beforedelete callback run.this improves performance, may not ideal circumstances.

now @ records in database

authors table =================== id    name     =================== 1     first author 2     second author  3     third author

books table

================================== id   title   isbn       author_id ==================================   1    abc    6416446846   1 2    xyz    3146354313   1 3    pqr    8945468485   2 4    fgh    6434164656   2 5    rtt    1215445644   3

now if delete record of author,all associated books particular author deleted.


-

Comments

Post a Comment

Popular posts from this blog

scala - 'wrong top statement declaration' when using slick in IntelliJ -

Image
i'm porting project scala 2.9 2.10, therefore have use slick instead of scalaquery. i'm using slick 2.1.0 since supports ms access. according this tutorial , upgrade guide changed robs object class , added val robs : why error message wrong top statement declaration , how rid of it? edit: i'm new scala... according this question seems can't put val outside of methods or classes, right? code above directly in packge. right approach slick then? should move code in class or trait? according this changed val robs = tablequery[robs] to object robs extends tablequery(new robs(_)) {} . no warnings or errors anymore. :)
Read more

c# - DevExpress.Wpf.Grid.InfiniteGridSizeException was unhandled -

Image
when using devexpress, see error: devexpress.wpf.grid.infinitegridsizeexception unhandled message="by default, infinite grid height not allowed since grid rows rendered , hence grid work slowly. fix issue, should place grid container give finite height grid, or should manually specify grid's height or maxheight. note can avoid exception setting gridcontrol.allowinfinitegridsize static property true, in case grid run slowly." the problem dxgrid has infinite height. to fix, set height non-infinite. snoop absolutely invaluable this: if "height" xaml element infinite (i.e. 0 or nan ), can set using one of following: option 1: height="{binding path=actualheight, relativesource={relativesource mode=findancestor, ancestortype=uielement}}" option 2: verticalalignment="stretch" option 3: height="auto" hint: use verticalalignment="stretch" if child of grid <rowdefinition height=
Read more

PySide and Qt Properties: Connecting signals from Python to QML -

i trying run simple pyside appliccation design made in qml. call function in qml python in separated thread. i have following qml view: import qt 4.7 rectangle { visible: true width: 100; height: 100 color: "lightgrey" text { id: datestr objectname: "datestr" x: 10 y: 10 text: "init text" font.pixelsize: 12 function updatedata(text) { datestr.text = qstr(text) console.log("you said: " + text) } } } here application: some imports.... #!/usr/bin/python import sys import time pyside import qtdeclarative, qtcore pyside.qtgui import qapplication pyside.qtdeclarative import qdeclarativeview the qthread worker.... #worker thread class worker(qtcore.qthread): updateprogress = qtcore.signal(int) def __init__(self, child): qtcore.qthread.__init__(self) self.child = child def run(self):
Read more