Python 如何在sqlalchemy中向表添加自定义的任意选项?
我正在尝试使用sqlalchemy的Python 如何在sqlalchemy中向表添加自定义的任意选项?,python,sqlalchemy,cockroachdb,Python,Sqlalchemy,Cockroachdb,我正在尝试使用sqlalchemy的声明性_base创建一个表,我想添加蟑螂B的在父项中交错选项: CREATE TABLE orders ( customer INT, id INT, total DECIMAL(20, 5), PRIMARY KEY (customer, id), CONSTRAINT fk_customer FOREIGN KEY (customer) REFERENCES customers ) INTERLEAVE IN P
声明性_base
创建一个表,我想添加蟑螂B
的在父项中交错
选项:
CREATE TABLE orders (
customer INT,
id INT,
total DECIMAL(20, 5),
PRIMARY KEY (customer, id),
CONSTRAINT fk_customer FOREIGN KEY (customer) REFERENCES customers
) INTERLEAVE IN PARENT customers (customer);
如何将其添加到DDL中?在蟑螂方言正式实施之前,您可以自己对其进行扩充,以实现所需的选项:
from sqlalchemy import Table, util
from sqlalchemy.schema import CreateTable
from sqlalchemy.ext.compiler import compiles
Table.argument_for("cockroachdb", "interleave_in_parent", None)
@compiles(CreateTable, "cockroachdb")
def compile_create_table(create, compiler, **kw):
preparer = compiler.preparer
stmt = compiler.visit_create_table(create, **kw)
cockroachdb_opts = create.element.dialect_options["cockroachdb"]
interleave = cockroachdb_opts.get("interleave_in_parent")
if interleave:
p_tbl, c_cols = interleave
parent_tbl = preparer.format_table(p_tbl)
child_cols = ", ".join([
preparer.quote(c)
if isinstance(c, util.string_types) else
preparer.format_column(c)
for c in c_cols
])
stmt = stmt.rstrip() # Prettier output, remove newlines
stmt = f"{stmt} INTERLEAVE IN PARENT {parent_tbl} ({child_cols})\n\n"
return stmt
然后像这样使用它:
class Customer(Base):
...
class Order(Base):
customer = Column(...)
...
__table_args__ = {
"cockroachdb_interleave_in_parent": (Customer.__table__, [customer])
}