我有一个来自OfBiz安装的预定义PostgreSQL数据库。该数据库有许多外键组件。我正在尝试编写一个python程序，将数据从生产数据库复制到临时或开发数据库。
最后一步是从我的数据集中清除一些开发人员不应该看到的私有数据。
我的反思设置如下：
def reflectSourceTables():
global Base
Base = automap_base(metadata = smeta)
global baseNum
baseNum = 0
Base.prepare(name_for_collection_relationship=_name_for_collection_relationship, name_for_scalar_relationship=_name_for_scalar_relationship, generate_relationship=_generate_relationship)
我的反思如下
def _name_for_scalar_relationship(base, local_cls, referred_cls, constraint):
global baseNum
if constraint.name:
baseNum += 1
disc = '_'.join(col.name for col in constraint.columns)
return referred_cls.__name__.lower() + '.' + disc + "_scalar_" + str(baseNum)
# if this didn't work, revert to the default behavior
return name_for_scalar_relationship(base, local_cls, referred_cls, constraint)
def _name_for_collection_relationship(base, local_cls, referred_cls, constraint):
global baseNum
if constraint.name:
baseNum += 1
disc = '_'.join(col.name for col in constraint.columns)
return referred_cls.__name__.lower() + '.' + disc + "_collection_" + str(baseNum)
# if this didn't work, revert to the default behavior
return name_for_collection_relationship(base, local_cls, referred_cls, constraint)
def _generate_relationship(base, direction, return_fn, attrname, local_cls, referred_cls, **kw):
if direction is interfaces.ONETOMANY:
kw['cascade'] = 'all, delete-orphan'
kw['passive_deletes'] = True
return generate_relationship(base, direction, return_fn, attrname, local_cls, referred_cls, **kw)
我能够通过以下代码看到表之间的关系：
def getTableList(smeta):
tableList = []
if args.tables:
##Validate tables are in database
for table in args.tables:
if smeta.tables[table] in smeta.sorted_tables:
tableList.append(str(smeta.tables[table]))
else:
log('Table {0} does not exist on source'.format(table))
else:
tableList = smeta.sorted_tables
if args.tables:
for table in tableList:
for relationship in getattr(Base.classes,str(table)).__mapper__.relationships:
#print(relationship)
tableName = re.search(r'\.(.*)\.', str(relationship)).group(1)
if tableName and tableName not in tableList:
tableList.append(tableName)
return tableList
但我希望删除代码：
def cleanData():
log("Clean Data")
destSession = sessionmaker()
destSess = destSession(bind=db2)
for partyId in partyIds:
log("Cleaning data for {0}".format(partyId))
voucher = Base.classes.voucher
invoice = Base.classes.invoice
voucherDelete = destSess.query(voucher).filter_by(party_id=partyId)
voucherDelete.delete(synchronize_session=False)
invoiceDelete = destSess.query(invoice).filter_by(party_id_from=partyId)
invoiceDelete.delete(synchronize_session=False)
destSess.commit()
删除会删除凭证和发票，但不会删除子invoice_item记录。
我的数据库设置不包括外键的级联删除功能，但我希望我可以让ORM提供功能。
理想情况下，此代码会删除凭证或发票的子项。
新关系的产生如下：
def _generate_relationship(base, direction, return_fn, attrname, local_cls, referred_cls, **kw):
## Write this to include cascade delete see: https://docs.sqlalchemy.org/en/latest/orm/extensions/automap.html#custom-relationship-arguments
if direction is interfaces.ONETOMANY or direction is interfaces.MANYTOMANY:
kw['cascade'] = 'all, delete, delete-orphan'
kw['passive_deletes'] = False
if direction is interfaces.MANYTOONE:
kw['viewonly'] = True
return generate_relationship(base, direction, return_fn, attrname, local_cls, referred_cls, **kw)
删除代码更改为：
voucher = Base.classes.voucher
invoice = Base.classes.invoice
invoiceDelete = destSess.query(invoice).filter_by(party_id_from=partyId)
rs = invoiceDelete.all()
for result in rs:
destSess.delete(result)
voucherDelete = destSess.query(voucher).filter_by(party_id=partyId)
rs = voucherDelete.all()
for result in rs:
destSess.delete(result)
destSess.commit()
这会导致以下错误：
sqlalchemy.exc.IntegrityError: (psycopg2.IntegrityError) update or delete on table "invoice_item" violates foreign key constraint "invoice_imat_itm" on table "invoice_item_attribute"
DETAIL: Key (invoice_id, invoice_item_seq_id)=(19439, 00001) is still referenced from table "invoice_item_attribute".
[SQL: 'DELETE FROM invoice_item WHERE invoice_item.invoice_id = %(invoice_id)s AND invoice_item.invoice_item_seq_id = %(invoice_item_seq_id)s'] [parameters: ({'invoice_id': '19439', 'invoice_item_seq_id': '00001'}, {'invoice_id': '33674', 'invoice_item_seq_id': '00001'}, {'invoice_id': '49384', 'invoice_item_seq_id': '00001'}, {'invoice_id': '58135', 'invoice_item_seq_id': '00001'}, {'invoice_id': '83457', 'invoice_item_seq_id': '00001'})] (Background on this error at: http://sqlalche.me/e/gkpj)
以下配置允许我删除数据库中凭证和发票的子记录。
关系自动映射器设置如下：
def _generate_relationship(base, direction, return_fn, attrname, local_cls, referred_cls, **kw):
## Write this to include cascade delete see: https://docs.sqlalchemy.org/en/latest/orm/extensions/automap.html#custom-relationship-arguments
if direction is interfaces.ONETOMANY:
kw['cascade'] = 'all, delete, delete-orphan'
kw['passive_deletes'] = False
kw['lazy'] = 'immediate'
if direction is interfaces.MANYTOONE or direction is interfaces.MANYTOMANY:
kw['viewonly'] = True
return generate_relationship(base, direction, return_fn, attrname, local_cls, referred_cls, **kw)
删除代码是：
def cleanData():
for partyId in partyIds:
log("Cleaning data for {0}".format(partyId))
invoice = Base.classes.invoice
invoiceDelete = destSess.query(invoice).filter_by(party_id_from=partyId)
rs = invoiceDelete.all()
for result in rs:
deleteChildren(result, destSess)
destSess.delete(result)
destSess.commit()
voucher = Base.classes.voucher
voucherDelete = destSess.query(voucher).filter_by(party_id=partyId)
rs = voucherDelete.all()
for result in rs:
deleteChildren(result, destSess)
destSess.delete(result)
destSess.commit()
def deleteChildren(result, destSess):
for relationship in result.__mapper__.relationships:
if relationship.direction is interfaces.ONETOMANY:
childs = getattr(result, str(re.search(r'\.(.*)', str(relationship)).group(1)))
for child in childs:
if child.__mapper__.relationships:
deleteChildren(child, destSess)
destSess.commit()
destSess.delete(child)
destSess.commit()
为了解释，我得到了与我想要从数据库中删除的聚会ID相关的记录，并使用递归方法使用急切提取从我定义的关系中获取子项。如果该子记录有子项，我会调用相同的方法。当我用完一对多关系时，我会删除记录并返回其父记录，同时删除该记录。