# XML-database conversion

from xml.dom import Node

import db_util

import xml_util

from xml_util import name_of

ptr_suffix = '_id'

def is_ptr(node_name): return node_name.endswith(ptr_suffix)

def ptr_type(node_name):

    assert is_ptr(node_name)

    return node_name[:-len(ptr_suffix)]

def ptr_target(node):

    assert is_ptr(name_of(node))

    return xml_util.first_elem(node)

def pkey_name(node_name): return node_name+ptr_suffix

def field_name(node_name):

def is_db_export(node_name): return node_name.find('.') >= 1 # has prefix

def find_by_name(node, name):

    for parent in xml_util.NodeParentIter(node):

        if name_of(parent) == name: return parent

        else:

            for child in xml_util.NodeElemIter(parent):

                child_name = field_name(name_of(child))

                if is_ptr(child_name):

                    if ptr_type(child_name) == name: return ptr_target(child)

                elif child_name == name: return child

    return None

def xml2db(node, db):

    def pkey(table):

        if table not in pkeys: pkeys[table] = db_util.pkey(db, table)

        return pkeys[table]

    def main(node):

        db_util.check_name(table)

        children = []

        iter_ = xml_util.NodeElemIter(node)

        # Skip any pkey

        child_name = name_of(iter_.curr()) # first child

        if is_db_export(child_name) and is_ptr(child_name)\

        or field_name(child_name) == pkey: iter_.next()

        # Divide children into fields and children with fkeys to parent

        for child in iter_:

        # Add fkey to parent

        parent_id = xml_util.get_id(node.parentNode)

        # Insert node

        for try_num in range(2):

            try:

                xml_util.set_id(node, db_util.insert_or_get(db, table, row,

            except db_util.NullValueException, ex:

                if try_num > 0: raise # exception still raised after retry

                if target == None: raise

                row[ex.col] = xml_util.get_id(target)

        # Insert children with fkeys to parent

        else:

            child = xml_util.first_elem(node)

        return (field_name(name_of(node)), value)

    row_ct_ref = [0]