技術メモ: "where ANCESTOR IS :1", oya

2008年6月27日金曜日

"where ANCESTOR IS :1", oya_key

http://googleappengine.blogspot.com/2008/04/posted-by-ken-ashcraft-software.html

Avoid large entity groups. Any two entities that share a common ancestor belong to the same entity groups. All writes to an entity group are sequential, so large entity groups can bog down popular apps quickly if there are a lot of writes to that group. Instead, use small, localized groups in your design.

#490 のようなbugはあるようだけれども


NewBand = Band(Name="Test", URL="Test", Description="A test description")
NewBand.put()

NewSection = Section(parent=NewBand, Title="News", URL="News", Type="News")
NewSection.put()

子のput ()の際に parent を設定しておけば、ancector is に親キーを指定して、検索する
ことができる。


oya_key = db.GqlQuery("select * from Band")[0].key()
ko = db.GqlQuery("select * from Section where ANCESTOR IS :1", oya_key )

http://groups.google.com/group/google-appengine/browse_thread/thread/ad5175429f2f61f2
App works locally, but fails when uploaded
x = Section.all().ancestor(self).filter("URL = ", SectionURL).get

SQL and GQL　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　TOP

is null	from google.appengine.ext import db r = db.GqlQuery ("SELECT * FROM model WHERE property=:1",None) # None is the python Null. / see
count(*)	r.count()
like	r = db.GqlQuery("SELECT * FROM model WHERE property >= :1 and property < :2 ", search_key, urllib.unquote(search_key).decode("utf8") + u"\uFFFD" )
update	see
!=	!= # see
date	yymm = '2008-05-10 22:22:22' # see ydate = datetime.datetime.strptime(yymm, '%Y-%m-%d %H:%M:%S')
日付検索	from datetime import * import datetime d1 = datetime.datetime.strptime('2008-06-01', '%Y-%m-%d') d2 = d1 + timedelta(days=10) r = db.GqlQuery("select * from model where date >=:1 and date <:2 ",d1,d2) 　for rr in r: print datetime.datetime.strftime(rr,'%Y-%m-%d %H:%M:%S') Dates and Times
	datastore viewer http://localhost:8080/_ah/admin/datastore?kind=StockSum&order=-nikkei_max&order_type=float&num=100&start=0
reference	see (back-references), Many-to-many Join
key, key_name ,id	Key names and IDs cannot be used like property values × select * from Greeting where key = "xxxx" × select * from Greeting where id = xxx ○ r = Greeting.get(db.Key.from_path('Greeting', id)) # or key_name ○ r = db.get("agpoZWxsb3dvcmxkcgsLEgRCbG9nGNQBDA") key = r.key() id = r.key().id()

2008年6月27日金曜日

"where ANCESTOR IS :1", oya_key

Swift+VSCodeでまた「一致するワークスペースシンボルがありません」で悩む