diff options
Diffstat (limited to 'examples/elementtree/optimized_al.py')
| -rw-r--r-- | examples/elementtree/optimized_al.py | 83 |
1 files changed, 49 insertions, 34 deletions
diff --git a/examples/elementtree/optimized_al.py b/examples/elementtree/optimized_al.py index 8e9c48b96..b66ada19d 100644 --- a/examples/elementtree/optimized_al.py +++ b/examples/elementtree/optimized_al.py @@ -7,28 +7,32 @@ """ -##################### PART I - Imports/Configuration ######################### -from sqlalchemy import ( - MetaData, - Table, - Column, - Integer, - String, - ForeignKey, - Unicode, - and_, - create_engine, -) -from sqlalchemy.orm import mapper, relationship, Session, lazyload - -import sys, os, io, re +# PART I - Imports/Configuration +import io +import os +import re from xml.etree import ElementTree +from sqlalchemy import and_ +from sqlalchemy import Column +from sqlalchemy import create_engine +from sqlalchemy import ForeignKey +from sqlalchemy import Integer +from sqlalchemy import MetaData +from sqlalchemy import String +from sqlalchemy import Table +from sqlalchemy import Unicode +from sqlalchemy.orm import lazyload +from sqlalchemy.orm import mapper +from sqlalchemy.orm import relationship +from sqlalchemy.orm import Session + + e = create_engine("sqlite://", echo=True) meta = MetaData() -####################### PART II - Table Metadata ############################# +# PART II - Table Metadata # stores a top level record of an XML document. documents = Table( @@ -68,10 +72,12 @@ attributes = Table( meta.create_all(e) -########################### PART III - Model ################################# +# PART III - Model # our document class. contains a string name, # and the ElementTree root element. + + class Document(object): def __init__(self, name, element): self.filename = name @@ -83,19 +89,22 @@ class Document(object): return buf.getvalue() -########################## PART IV - Persistence Mapping ##################### +# PART IV - Persistence Mapping + +# Node class. a non-public class which will represent the DB-persisted +# Element/SubElement object. We cannot create mappers for ElementTree elements +# directly because they are at the very least not new-style classes, and also +# may be backed by native implementations. so here we construct an adapter. + -# Node class. a non-public class which will represent -# the DB-persisted Element/SubElement object. We cannot create mappers for -# ElementTree elements directly because they are at the very least not new-style -# classes, and also may be backed by native implementations. -# so here we construct an adapter. class _Node(object): pass -# Attribute class. also internal, this will represent the key/value attributes stored for -# a particular Node. +# Attribute class. also internal, this will represent the key/value attributes +# stored for a particular Node. + + class _Attribute(object): def __init__(self, name, value): self.name = name @@ -115,10 +124,11 @@ mapper( }, ) -# the _Node objects change the way they load so that a list of _Nodes will organize -# themselves hierarchically using the ElementTreeMarshal. this depends on the ordering of -# nodes being hierarchical as well; relationship() always applies at least ROWID/primary key -# ordering to rows which will suffice. +# the _Node objects change the way they load so that a list of _Nodes will +# organize themselves hierarchically using the ElementTreeMarshal. this +# depends on the ordering of nodes being hierarchical as well; relationship() +# always applies at least ROWID/primary key ordering to rows which will +# suffice. mapper( _Node, elements, @@ -134,9 +144,12 @@ mapper( mapper(_Attribute, attributes) -# define marshalling functions that convert from _Node/_Attribute to/from ElementTree objects. -# this will set the ElementTree element as "document._element", and append the root _Node -# object to the "_nodes" mapped collection. +# define marshalling functions that convert from _Node/_Attribute to/from +# ElementTree objects. this will set the ElementTree element as +# "document._element", and append the root _Node object to the "_nodes" mapped +# collection. + + class ElementTreeMarshal(object): def __get__(self, document, owner): if document is None: @@ -188,7 +201,7 @@ class ElementTreeMarshal(object): # override Document's "element" attribute with the marshaller. Document.element = ElementTreeMarshal() -###################### PART V - Basic Persistence Example #################### +# PART V - Basic Persistence Example line = "\n--------------------------------------------------------" @@ -210,7 +223,7 @@ document = session.query(Document).filter_by(filename="test.xml").first() print(document) -######################## PART VI - Searching for Paths ####################### +# PART VI - Searching for Paths # manually search for a document which contains "/somefile/header/field1:hi" print("\nManual search for /somefile/header/field1=='hi':", line) @@ -227,6 +240,8 @@ d = ( print(d) # generalize the above approach into an extremely impoverished xpath function: + + def find_document(path, compareto): j = documents prev_elements = None |