{"id":2928,"date":"2021-07-21T08:31:12","date_gmt":"2021-07-21T08:31:12","guid":{"rendered":"https:\/\/www.bearloga.space\/?page_id=2928"},"modified":"2021-07-21T08:31:12","modified_gmt":"2021-07-21T08:31:12","slug":"sqlalchemy-orm-rabota-s-obedineniyami","status":"publish","type":"page","link":"https:\/\/www.bearloga.space\/uk\/sqlalchemy-orm-rabota-s-obedineniyami\/","title":{"rendered":"SQLAlchemy ORM \u2014 \u0420\u0430\u0431\u043e\u0442\u0430 \u0441 \u043e\u0431\u044a\u0435\u0434\u0438\u043d\u0435\u043d\u0438\u044f\u043c\u0438"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">\u0422\u0435\u043f\u0435\u0440\u044c, \u043a\u043e\u0433\u0434\u0430 \u0443 \u043d\u0430\u0441 \u0435\u0441\u0442\u044c \u0434\u0432\u0435 \u0442\u0430\u0431\u043b\u0438\u0446\u044b, \u043c\u044b \u0443\u0432\u0438\u0434\u0438\u043c, \u043a\u0430\u043a \u0441\u043e\u0437\u0434\u0430\u0432\u0430\u0442\u044c \u0437\u0430\u043f\u0440\u043e\u0441\u044b \u0434\u043b\u044f \u043e\u0431\u0435\u0438\u0445 \u0442\u0430\u0431\u043b\u0438\u0446 \u043e\u0434\u043d\u043e\u0432\u0440\u0435\u043c\u0435\u043d\u043d\u043e.&nbsp;\u0427\u0442\u043e\u0431\u044b \u0441\u043e\u0437\u0434\u0430\u0442\u044c \u043f\u0440\u043e\u0441\u0442\u043e\u0435 \u043d\u0435\u044f\u0432\u043d\u043e\u0435 \u0441\u043e\u0435\u0434\u0438\u043d\u0435\u043d\u0438\u0435 \u043c\u0435\u0436\u0434\u0443 Customer \u0438 Invoice, \u043c\u044b \u043c\u043e\u0436\u0435\u043c \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u044c Query.filter (), \u0447\u0442\u043e\u0431\u044b \u043f\u0440\u0438\u0440\u0430\u0432\u043d\u044f\u0442\u044c \u0438\u0445 \u0441\u0432\u044f\u0437\u0430\u043d\u043d\u044b\u0435 \u0441\u0442\u043e\u043b\u0431\u0446\u044b.&nbsp;\u041d\u0438\u0436\u0435 \u043c\u044b \u0441\u0440\u0430\u0437\u0443 \u0437\u0430\u0433\u0440\u0443\u0436\u0430\u0435\u043c \u043e\u0431\u044a\u0435\u043a\u0442\u044b Customer \u0438 Invoice, \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u0443\u044f \u044d\u0442\u043e\u0442 \u043c\u0435\u0442\u043e\u0434 \u2014<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">from sqlalchemy.orm import sessionmaker\nSession = sessionmaker(bind = engine)\nsession = Session()\n\nfor c, i in session.query(Customer, Invoice).filter(Customer.id == Invoice.custid).all():\n   print (\"ID: {} Name: {} Invoice No: {} Amount: {}\".format(c.id,c.name, i.invno, i.amount))<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\u0412\u044b\u0440\u0430\u0436\u0435\u043d\u0438\u0435 SQL, \u0433\u0435\u043d\u0435\u0440\u0438\u0440\u0443\u0435\u043c\u043e\u0435 SQLAlchemy, \u0432\u044b\u0433\u043b\u044f\u0434\u0438\u0442 \u0441\u043b\u0435\u0434\u0443\u044e\u0449\u0438\u043c \u043e\u0431\u0440\u0430\u0437\u043e\u043c:<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">SELECT customers.id \nAS customers_id, customers.name \nAS customers_name, customers.address \nAS customers_address, customers.email \nAS customers_email, invoices.id \nAS invoices_id, invoices.custid \nAS invoices_custid, invoices.invno \nAS invoices_invno, invoices.amount \nAS invoices_amount\nFROM customers, invoices\nWHERE customers.id = invoices.custid<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\u0418 \u0440\u0435\u0437\u0443\u043b\u044c\u0442\u0430\u0442 \u043f\u0440\u0438\u0432\u0435\u0434\u0435\u043d\u043d\u044b\u0445 \u0432\u044b\u0448\u0435 \u0441\u0442\u0440\u043e\u043a \u043a\u043e\u0434\u0430 \u0432\u044b\u0433\u043b\u044f\u0434\u0438\u0442 \u0441\u043b\u0435\u0434\u0443\u044e\u0449\u0438\u043c \u043e\u0431\u0440\u0430\u0437\u043e\u043c:<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">ID: 2 Name: Gopal Krishna Invoice No: 10 Amount: 15000\nID: 2 Name: Gopal Krishna Invoice No: 14 Amount: 3850\nID: 3 Name: Govind Pant Invoice No: 3 Amount: 10000\nID: 3 Name: Govind Pant Invoice No: 4 Amount: 5000\nID: 4 Name: Govind Kala Invoice No: 7 Amount: 12000\nID: 4 Name: Govind Kala Invoice No: 8 Amount: 8500\nID: 5 Name: Abdul Rahman Invoice No: 9 Amount: 15000\nID: 5 Name: Abdul Rahman Invoice No: 11 Amount: 6000\n<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\u0424\u0430\u043a\u0442\u0438\u0447\u0435\u0441\u043a\u0438\u0439 \u0441\u0438\u043d\u0442\u0430\u043a\u0441\u0438\u0441 SQL JOIN \u043b\u0435\u0433\u043a\u043e \u0434\u043e\u0441\u0442\u0438\u0433\u0430\u0435\u0442\u0441\u044f \u0441 \u043f\u043e\u043c\u043e\u0449\u044c\u044e \u043c\u0435\u0442\u043e\u0434\u0430 Query.join () \u0441\u043b\u0435\u0434\u0443\u044e\u0449\u0438\u043c \u043e\u0431\u0440\u0430\u0437\u043e\u043c:<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">session.query(Customer).join(Invoice).filter(Invoice.amount == 8500).all()<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\u0412\u044b\u0440\u0430\u0436\u0435\u043d\u0438\u0435 SQL \u0434\u043b\u044f \u043e\u0431\u044a\u0435\u0434\u0438\u043d\u0435\u043d\u0438\u044f \u0431\u0443\u0434\u0435\u0442 \u043e\u0442\u043e\u0431\u0440\u0430\u0436\u0430\u0442\u044c\u0441\u044f \u043d\u0430 \u043a\u043e\u043d\u0441\u043e\u043b\u0438 \u2014<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">SELECT customers.id \nAS customers_id, customers.name \nAS customers_name, customers.address \nAS customers_address, customers.email \nAS customers_email\nFROM customers JOIN invoices ON customers.id = invoices.custid\nWHERE invoices.amount = ?<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\u041c\u044b \u043c\u043e\u0436\u0435\u043c \u043f\u0435\u0440\u0435\u0431\u0440\u0430\u0442\u044c \u0440\u0435\u0437\u0443\u043b\u044c\u0442\u0430\u0442, \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u0443\u044f \u0446\u0438\u043a\u043b for \u2014<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">result = session.query(Customer).join(Invoice).filter(Invoice.amount == 8500)\nfor row in result:\n   for inv in row.invoices:\n      print (row.id, row.name, inv.invno, inv.amount)<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\u041f\u0440\u0438 8500 \u0432 \u043a\u0430\u0447\u0435\u0441\u0442\u0432\u0435 \u043f\u0430\u0440\u0430\u043c\u0435\u0442\u0440\u0430 \u0441\u0432\u044f\u0437\u044b\u0432\u0430\u043d\u0438\u044f \u043e\u0442\u043e\u0431\u0440\u0430\u0436\u0430\u0435\u0442\u0441\u044f \u0441\u043b\u0435\u0434\u0443\u044e\u0449\u0438\u0439 \u0432\u044b\u0432\u043e\u0434:<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">4 Govind Kala 8 8500  \n<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">Query.join () \u0437\u043d\u0430\u0435\u0442, \u043a\u0430\u043a \u0441\u043e\u0435\u0434\u0438\u043d\u0438\u0442\u044c \u044d\u0442\u0438 \u0442\u0430\u0431\u043b\u0438\u0446\u044b, \u043f\u043e\u0442\u043e\u043c\u0443 \u0447\u0442\u043e \u043c\u0435\u0436\u0434\u0443 \u043d\u0438\u043c\u0438 \u0435\u0441\u0442\u044c \u0442\u043e\u043b\u044c\u043a\u043e \u043e\u0434\u0438\u043d \u0432\u043d\u0435\u0448\u043d\u0438\u0439 \u043a\u043b\u044e\u0447.&nbsp;\u0415\u0441\u043b\u0438 \u043d\u0435 \u0431\u044b\u043b\u043e \u0432\u043d\u0435\u0448\u043d\u0438\u0445 \u043a\u043b\u044e\u0447\u0435\u0439 \u0438\u043b\u0438 \u0431\u044b\u043b\u043e \u0431\u043e\u043b\u044c\u0448\u0435 \u0432\u043d\u0435\u0448\u043d\u0438\u0445 \u043a\u043b\u044e\u0447\u0435\u0439, Query.join () \u0440\u0430\u0431\u043e\u0442\u0430\u0435\u0442 \u043b\u0443\u0447\u0448\u0435, \u043a\u043e\u0433\u0434\u0430 \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u0443\u0435\u0442\u0441\u044f \u043e\u0434\u043d\u0430 \u0438\u0437 \u0441\u043b\u0435\u0434\u0443\u044e\u0449\u0438\u0445 \u0444\u043e\u0440\u043c:<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td>query.join (\u0421\u0447\u0435\u0442, id == Address.custid)<\/td><td>\u044f\u0432\u043d\u043e\u0435 \u0443\u0441\u043b\u043e\u0432\u0438\u0435<\/td><\/tr><tr><td>query.join (Customer.invoices)<\/td><td>\u0443\u043a\u0430\u0437\u0430\u0442\u044c \u043e\u0442\u043d\u043e\u0448\u0435\u043d\u0438\u044f \u0441\u043b\u0435\u0432\u0430 \u043d\u0430\u043f\u0440\u0430\u0432\u043e<\/td><\/tr><tr><td>query.join (Invoice, Customer.invoices)<\/td><td>\u0442\u043e \u0436\u0435 \u0441\u0430\u043c\u043e\u0435, \u0441 \u044f\u0432\u043d\u043e\u0439 \u0446\u0435\u043b\u044c\u044e<\/td><\/tr><tr><td>query.join ( \u2018\u0441\u0447\u0435\u0442\u0430\u2019)<\/td><td>\u0442\u043e \u0436\u0435 \u0441\u0430\u043c\u043e\u0435, \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u0443\u044f \u0441\u0442\u0440\u043e\u043a\u0443<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">\u0422\u043e\u0447\u043d\u043e \u0442\u0430\u043a \u0436\u0435 \u0444\u0443\u043d\u043a\u0446\u0438\u044f externaljoin () \u0434\u043e\u0441\u0442\u0443\u043f\u043d\u0430 \u0434\u043b\u044f \u0434\u043e\u0441\u0442\u0438\u0436\u0435\u043d\u0438\u044f \u0432\u043d\u0435\u0448\u043d\u0435\u0433\u043e \u043b\u0435\u0432\u043e\u0433\u043e \u0441\u043e\u0435\u0434\u0438\u043d\u0435\u043d\u0438\u044f.<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">query.outerjoin(Customer.invoices)<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\u041c\u0435\u0442\u043e\u0434 subquery () \u0441\u043e\u0437\u0434\u0430\u0435\u0442 \u0432\u044b\u0440\u0430\u0436\u0435\u043d\u0438\u0435 SQL, \u043f\u0440\u0435\u0434\u0441\u0442\u0430\u0432\u043b\u044f\u044e\u0449\u0435\u0435 \u0438\u043d\u0441\u0442\u0440\u0443\u043a\u0446\u0438\u044e SELECT, \u0432\u0441\u0442\u0440\u043e\u0435\u043d\u043d\u0443\u044e \u0432 \u043f\u0441\u0435\u0432\u0434\u043e\u043d\u0438\u043c.<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">from sqlalchemy.sql import func\n\nstmt = session.query(\n   Invoice.custid, func.count('*').label('invoice_count')\n).group_by(Invoice.custid).subquery()<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\u041e\u0431\u044a\u0435\u043a\u0442 stmt \u0431\u0443\u0434\u0435\u0442 \u0441\u043e\u0434\u0435\u0440\u0436\u0430\u0442\u044c \u0438\u043d\u0441\u0442\u0440\u0443\u043a\u0446\u0438\u044e SQL, \u043a\u0430\u043a \u043f\u043e\u043a\u0430\u0437\u0430\u043d\u043e \u043d\u0438\u0436\u0435:<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">SELECT invoices.custid, count(:count_1) AS invoice_count FROM invoices GROUP BY invoices.custid<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\u041a\u043e\u0433\u0434\u0430 \u0443 \u043d\u0430\u0441 \u0435\u0441\u0442\u044c \u043d\u0430\u0448\u0435 \u0443\u0442\u0432\u0435\u0440\u0436\u0434\u0435\u043d\u0438\u0435, \u043e\u043d\u043e \u0432\u0435\u0434\u0435\u0442 \u0441\u0435\u0431\u044f \u043a\u0430\u043a \u043a\u043e\u043d\u0441\u0442\u0440\u0443\u043a\u0446\u0438\u044f \u0442\u0430\u0431\u043b\u0438\u0446\u044b.&nbsp;\u0421\u0442\u043e\u043b\u0431\u0446\u044b \u0432 \u0432\u044b\u0440\u0430\u0436\u0435\u043d\u0438\u0438 \u0434\u043e\u0441\u0442\u0443\u043f\u043d\u044b \u0447\u0435\u0440\u0435\u0437 \u0430\u0442\u0440\u0438\u0431\u0443\u0442 \u0441 \u0438\u043c\u0435\u043d\u0435\u043c c, \u043a\u0430\u043a \u043f\u043e\u043a\u0430\u0437\u0430\u043d\u043e \u0432 \u043f\u0440\u0438\u0432\u0435\u0434\u0435\u043d\u043d\u043e\u043c \u043d\u0438\u0436\u0435 \u043a\u043e\u0434\u0435 \u2014<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">for u, count in session.query(Customer, stmt.c.invoice_count).outerjoin(stmt, Customer.id == stmt.c.custid).order_by(Customer.id):\n   print(u.name, count)<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>\u0422\u0435\u043f\u0435\u0440\u044c, \u043a\u043e\u0433\u0434\u0430 \u0443 \u043d\u0430\u0441 \u0435\u0441\u0442\u044c \u0434\u0432\u0435 \u0442\u0430\u0431\u043b\u0438\u0446\u044b, \u043c\u044b \u0443\u0432\u0438\u0434\u0438\u043c, \u043a\u0430\u043a \u0441\u043e\u0437\u0434\u0430\u0432\u0430\u0442\u044c \u0437\u0430\u043f\u0440\u043e\u0441\u044b \u0434\u043b\u044f \u043e\u0431\u0435\u0438\u0445 \u0442\u0430\u0431\u043b\u0438\u0446 \u043e\u0434\u043d\u043e\u0432\u0440\u0435\u043c\u0435\u043d\u043d\u043e.&nbsp;\u0427\u0442\u043e\u0431\u044b \u0441\u043e\u0437\u0434\u0430\u0442\u044c \u043f\u0440\u043e\u0441\u0442\u043e\u0435 \u043d\u0435\u044f\u0432\u043d\u043e\u0435 \u0441\u043e\u0435\u0434\u0438\u043d\u0435\u043d\u0438\u0435 [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"categories":[103],"tags":[],"class_list":["post-2928","page","type-page","status-publish","hentry","category-sqlalchemy"],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.bearloga.space\/uk\/wp-json\/wp\/v2\/pages\/2928","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.bearloga.space\/uk\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.bearloga.space\/uk\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.bearloga.space\/uk\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.bearloga.space\/uk\/wp-json\/wp\/v2\/comments?post=2928"}],"version-history":[{"count":0,"href":"https:\/\/www.bearloga.space\/uk\/wp-json\/wp\/v2\/pages\/2928\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.bearloga.space\/uk\/wp-json\/wp\/v2\/media?parent=2928"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bearloga.space\/uk\/wp-json\/wp\/v2\/categories?post=2928"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bearloga.space\/uk\/wp-json\/wp\/v2\/tags?post=2928"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}