peewee

问题 I'm trying to join two tables in peewee with a mysql database. This is pretty easy doing something like this: s = Table1.select(Table1, Table2).join( Table2).naive().where(Table1.Title == "whatever") Unfortunately, I have called a column in Table1 and Table2 the same thing, "URL". Then when I select s.URL it gives me the URL from Table2, which I don't want, I want the one from Table1. Is there some way to either not join the Table2.URL column or to name it something different? This question

问题 My CherryPy app does some cleaning every hour with the following code: def every_hour(): two_hours_ago = time.time() - 2 * 60 * 60 DbChoice.delete().where(DbChoice.time_stamp < two_hours_ago).execute() monitor_every_hour = Monitor(cherrypy.engine, every_hour, frequency=60 * 60) monitor_every_hour.start() Sometimes it crashes with he following message: Traceback (most recent call last): File "C:\Python34\lib\site-packages\peewee.py", line 2364, in execute_sql self.commit() File "C:\Python34

问题 Navigating to the page test?x=a defined below it works. Navigating to test?x=a and then quickly navigating to test?x=b , both the cycles will keep running for a few seconds, but one of them will eventually crash with the error peewee.OperationalError: cannot start a transaction within a transaction . This is obviously not a real world test, it is a way to reproduce the real world problems that I am having once in a while. In the real world application I see errors similar to this one when

问题 I'm using Python 2.7 together with Peewee. At this moment, I need to use Peewee to execute the following SQL query: select a, b, substring(c, 1, 3) as alias1, count(substring(c, 1, 3)) as alias2 from Table where <some where condition, not relevant here> group by a, alias1 My first problem here is how to perform a substring with Peewee. I have searched the documentation and, so far, no lucky. So, the basic question is: How do I perform a substring SQL function using Peewee? It would also be

问题 How can I update a tables columns and column data types in PeeWee? I have already created the table Person in the database from my model. But I've now added some new fields to the model and changed the type of certain existing fields/columns. The following doesn't update the table structure: psql_db = PostgresqlExtDatabase( 'MyDB', user='foo', password='bar', host='', port='5432', register_hstore=False ) class PsqlModel(Model): """A base model that will use our Postgresql database""" class

问题 I have a quick function that I threw up together to remove duplicates on my table given a particular combination of fields: for l in table.select(): if table.select().where((table.Field1==l.Field1) & (table.Field2==l.Field2) & ....).count()>1: l.delete() l.save() But I imagine that there's a better way to do this 回答1: You could add a unique constraint on the columns you wish to be unique, then let the database enforce the rules for you. That'd be the best way. For peewee, that looks like:

问题 Lets say I have import peewee class Foo(Model): name = CharField() I would like to do the following: f = {id:1, name:"bar"} foo = Foo.create_from_dict(f) Is this native in Peewee? I was unable to spot anything in the source code. I've wrote this function which works but would rather use the native function if it exists: #clazz is a string for the name of the Model, i.e. 'Foo' def model_from_dict(clazz, dictionary): #convert the string into the actual model class clazz = reduce(getattr, clazz

问题 I have the following python source file to retrieve rows from MySQL database. The problem is there are too many rows to retrieve in subscriber table. How can I do limit to small chunk of rows to retrieve and process and so on? class subinfo(peewee.Model): sub_id = peewee.IntegerField() active = peewee.BooleanField() sub_type = peewee.IntegerField() sub_cat = peewee.TextField() class Meta: database = locdb class subscriber(peewee.Model): sub_id = peewee.IntegerField(unique=True, primary_key

问题 I need to use some ORM engine, like peewee , for handling SQLite database within my python application. However, most of such libraries offer syntax like this to define models.py : import peewee db = peewee.Database('hello.sqlite') class Person(peewee.Model): name = peewee.CharField() class Meta: database = db However, in my application, i cannot use such syntax since database file name is provided by outside code after import, from module, which imports my models.py . How to initialize

问题 Assuming we have these three models. class Item(BaseModel): title = CharField() class User(BaseModel): name = CharField() class UserAnswer(BaseModel): user = ForeignKeyField(User, 'user_answers') item = ForeignKeyField(Item, 'user_answers_items') answer = ForeignKeyField(Item, 'user_answers') I want to get all Items which does not have related UserAnswer records for current user. In SQL it would be something like this: select * from item i left join useranswer ua on ua.item_id=i.id and ua