d2a 2.1.2

自动加载

只需将d2a添加到settings.INSTALLED_APPS。

INSTALLED_APPS=['django.contrib.admin','django.contrib.auth','django.contrib.contenttypes','django.contrib.sessions','django.contrib.messages','django.contrib.staticfiles',# top or here'd2a',# example apps'books','sales',]

然后，所有应用程序中的模型都将作为模块导入。

>>>frombooksimportmodels_sqla>>>models_sqla.# tab completionmodels_sqla.Author(models_sqla.BookCategory(models_sqla.CategoryRelation(models_sqla.transfer(models_sqla.Book(models_sqla.Category(models_sqla.models>>>models_sqla.Book<class'd2a.book'>>>>models_sqla.Book.# tab completionmodels_sqla.Book.authormodels_sqla.Book.contentmodels_sqla.Book.metadatamodels_sqla.Book.tagsmodels_sqla.Book.author_idmodels_sqla.Book.descriptionmodels_sqla.Book.mro(models_sqla.Book.titlemodels_sqla.Book.categorymodels_sqla.Book.idmodels_sqla.Book.price# SQL Expression schema>>>models_sqla.Book.__table__Table('book',MetaData(bind=None),Column('id',UUID(),table=<book>,primary_key=True,nullable=False,default=ColumnDefault(<functionuuid4at0x7f3cebe7e598>)),Column('price',JSON(astext_type=Text()),table=<book>,nullable=False),Column('title',VARCHAR(length=255),table=<book>,nullable=False),Column('description',TEXT(),table=<book>),Column('author_id',INTEGER(),ForeignKey('author.id'),table=<book>),Column('content',BYTEA(),table=<book>,nullable=False),Column('tags',ARRAY(VARCHAR()),table=<book>,nullable=False),schema=None)

此外，它还可以根据m2m字段提取隐式声明的模型。 （在这种情况下，图书类别）

# This variable can be omitted.D2A_CONFIG={'AUTOLOAD':{# optional# module name: It can be used different module name from `models_sqla`.'module':'modelsa',# optional, default: 'models_sqla'# waiting seconds during autoloading'seconds':5,# default: 1# transfer function's args after 'exports' arg.'option':{# optional'db_type':'postgresql',# default: 'default''back_type':'backref',# default: 'backref''as_table':True,# default: False'name_formatter':str.upper,# default: get_camelcase}},# converting rules for customized fields'ALIASES':{# optional# Evaluates ExtendedImageField as ImageFieldExtendedImageField:models.ImageField,},}

每个模型模块

如果要手动创建模块，请在应用程序中创建models_sqla.py。

按如下方式书写：

fromd2aimporttransferfrom.importmodelstransfer(models,globals())

如果您手动创建每个模型， 无需将d2a设置为settings.INSTALLED_APPS。

示例：

• project_postgresql/books/models_sqla.py
• 您可以省略指定数据库类型，然后它会自动检测来自settings.DATABASES['default']的数据库类型。
  • 现在允许postgresql，mysql和oracle， 其他类型将转换为default类型： sqlalchemy/types.py

每个型号

如果只想转换一个模型，应该使用declare函数。

>>>fromd2aimportdeclare>>>fromsales.modelsimportSales>>>sales=declare(Sales)>>>sales<class'd2a.sales'>>>>sales.__table__Table('sales',MetaData(bind=None),Column('id',BIGINT(),table=<sales>,primary_key=True,nullable=False),Column('book_id',UUID(),ForeignKey('book.id'),table=<sales>,nullable=False),Column('sold',TIMESTAMP(),table=<sales>,nullable=False),Column('reservation',INTERVAL(),table=<sales>),Column('source',INET(),table=<sales>),schema=None)>>>sales.sales.booksales.idsales.mro(sales.soldsales.book_idsales.metadatasales.reservationsales.source

自定义字段

如果您使用的是自定义字段（不是内置的）， 您可以使用alias或alias\u dict方法将该字段注册为另一个字段。

fromdjango.db.modelsimportImageFieldclassExtendedImageField(ImageField):"""something customizing"""fromd2aimportaliasalias(ExtendedImageField,ImageField)# oralias_dict({ExtendedImageField:ImageField,})

查询快捷方式

>>>fromd2aimportmake_session>>>frombooks.models_sqlaimportAuthor>>>withmake_session()assession:...# it commits and flushes automatically when the scope exits....a=Author()...a.name='righ'...a.age=30...session.add(a)...>>>withmake_session()assession:...# when the session was rolled back or causes some exception in the context,...# it won't register records in the session....a=Author()...a.name='teruhiko'...a.age=85...session.add(a)...session.rollback()...>>>withmake_session()assession:...session.query(Author.name,Author.age).all()...[('righ',30)]

>>>fromsqlalchemyimport(...select,...insert,...)>>>fromd2aimportquery_expression,execute_expression# if you try on `project_mysql` demo, you should write ``from books.modelsa import Author``>>>frombooks.models_sqlaimportAuthor>>>AuthorTable=Author.__table__>>>records=[...{'name':'a','age':10},...{'name':'b','age':30},...{'name':'c','age':20},...]>>># insert>>>stmt=insert(AuthorTable).values(records)>>>execute_expression(stmt)3>>># select>>>stmt=select([...AuthorTable.c.id,...AuthorTable.c.name,...AuthorTable.c.age,...]).select_from(AuthorTable).order_by(AuthorTable.c.age)>>>query_expression(stmt)[OrderedDict([('id',12),('name','a'),('age',10)]),OrderedDict([('id',14),('name','c'),('age',20)]),OrderedDict([('id',13),('name','b'),('age',30)])]>>># record as tuple>>>query_expression(stmt,as_col_dict=False)[(12,'a',10),(14,'c',20),(13,'b',30)]>>>query_expression(stmt,as_col_dict=False,debug={'printer':print,'show_explain':True,'sql_format':True})====================================================================================================SELECTauthor.id,author.name,author.ageFROMauthorORDERBYauthor.age====================================================================================================Sort(cost=16.39..16.74rows=140width=522)(actualtime=0.027..0.028rows=18loops=1)SortKey:ageSortMethod:quicksortMemory:25kB->SeqScanonauthor(cost=0.00..11.40rows=140width=522)(actualtime=0.007..0.009rows=18loops=1)Planningtime:0.072msExecutiontime:0.047ms[(12,'a',10),(14,'c',20),(13,'b',30)]

query_expression(stmt,debug={# all options can be skipped.'show_sql':True,# if showing the sql query or not.'show_explain':False,# if showing explain for the sql query or not.'sql_format':False,# if formatting the sql query or not.'sql_reindent':True,# if setting indent the sql query or not.'sql_keyword_case':'upper',# A rule converting reserved words.'explain_prefix':dependsonthedatabasetype.unlessyouspecifyit,anappropriateprefixwillbeautomaticallyused.'printer':logger.debug,# printing method, if you use python3, then try `print` function.'delimiter':'='*100,# characters dividing debug informations.'database':'default'# django database})

启动环境

$ git clone git@github.com:walkframe/d2a.git
$ cd d2a
$ docker-compose up

准备

$ docker exec -it d2a_app_1 /bin/bash
# python -m venv venv # only first time
# source venv/bin/activate
(venv)# cd project_postgresql/ # (or mysql)
(venv) project_postgresql # ./manage.py migrate

执行

(venv) project_postgresql # ./manage.py shell

>>>frombooksimportmodels_sqla>>>book=models_sqla.Book()>>>author=models_sqla.Author()>>>book.author=author>>>author.books[<d2a.bookobjectat0x7f3cec539358>]# And do something you want do ;)