99 lines
2.8 KiB
Python
99 lines
2.8 KiB
Python
from sqlalchemy.engine.url import make_url
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import sqlalchemy as sa
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from sqlalchemy.exc import ProgrammingError, OperationalError
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import os
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from copy import copy
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def database_exists(url):
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"""Check if a database exists.
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"""
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url = copy(make_url(url))
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database = url.database
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url.database = None
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engine = sa.create_engine(url)
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if engine.dialect.name == 'postgresql':
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text = "SELECT 1 FROM pg_database WHERE datname='%s'" % database
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return bool(engine.execute(text).scalar())
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elif engine.dialect.name == 'mysql':
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text = ("SELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA "
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"WHERE SCHEMA_NAME = '%s'" % database)
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return bool(engine.execute(text).scalar())
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elif engine.dialect.name == 'sqlite':
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return database == ':memory:' or os.path.exists(database)
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else:
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text = 'SELECT 1'
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try:
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url.database = database
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engine = sa.create_engine(url)
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engine.execute(text)
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return True
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except (ProgrammingError, OperationalError):
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return False
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def create_database(url, encoding='utf8'):
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"""Issue the appropriate CREATE DATABASE statement.
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"""
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url = copy(make_url(url))
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database = url.database
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if not url.drivername.startswith('sqlite'):
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url.database = None
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engine = sa.create_engine(url)
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if engine.dialect.name == 'postgresql':
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if engine.driver == 'psycopg2':
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from psycopg2.extensions import ISOLATION_LEVEL_AUTOCOMMIT
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engine.raw_connection().set_isolation_level(
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ISOLATION_LEVEL_AUTOCOMMIT)
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text = "CREATE DATABASE %s ENCODING = '%s'" % (database, encoding)
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engine.execute(text)
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elif engine.dialect.name == 'mysql':
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text = "CREATE DATABASE %s CHARACTER SET = '%s'" % (database, encoding)
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engine.execute(text)
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elif engine.dialect.name == 'sqlite' and database != ':memory:':
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open(database, 'w').close()
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else:
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text = "CREATE DATABASE %s" % database
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engine.execute(text)
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def drop_database(url):
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"""Issue the appropriate DROP DATABASE statement.
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"""
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url = copy(make_url(url))
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database = url.database
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if not url.drivername.startswith('sqlite'):
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url.database = None
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engine = sa.create_engine(url)
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if engine.dialect.name == 'sqlite' and url.database != ':memory:':
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os.remove(url.database)
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elif engine.dialect.name == 'postgresql' and engine.driver == 'psycopg2':
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from psycopg2.extensions import ISOLATION_LEVEL_AUTOCOMMIT
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engine.raw_connection().set_isolation_level(ISOLATION_LEVEL_AUTOCOMMIT)
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text = "DROP DATABASE %s" % database
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engine.execute(text)
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else:
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text = "DROP DATABASE %s" % database
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engine.execute(text)
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