python学习

venv/Lib/site-packages/sqlalchemy/connectors/pyodbc.py

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+# connectors/pyodbc.py
+# Copyright (C) 2005-2019 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: http://www.opensource.org/licenses/mit-license.php
+
+import re
+
+from . import Connector
+from .. import util
+
+
+class PyODBCConnector(Connector):
+    driver = "pyodbc"
+
+    supports_sane_rowcount_returning = False
+    supports_sane_multi_rowcount = False
+
+    supports_unicode_statements = True
+    supports_unicode_binds = True
+
+    supports_native_decimal = True
+    default_paramstyle = "named"
+
+    # for non-DSN connections, this *may* be used to
+    # hold the desired driver name
+    pyodbc_driver_name = None
+
+    def __init__(self, supports_unicode_binds=None, **kw):
+        super(PyODBCConnector, self).__init__(**kw)
+        if supports_unicode_binds is not None:
+            self.supports_unicode_binds = supports_unicode_binds
+
+    @classmethod
+    def dbapi(cls):
+        return __import__("pyodbc")
+
+    def create_connect_args(self, url):
+        opts = url.translate_connect_args(username="user")
+        opts.update(url.query)
+
+        keys = opts
+
+        query = url.query
+
+        connect_args = {}
+        for param in ("ansi", "unicode_results", "autocommit"):
+            if param in keys:
+                connect_args[param] = util.asbool(keys.pop(param))
+
+        if "odbc_connect" in keys:
+            connectors = [util.unquote_plus(keys.pop("odbc_connect"))]
+        else:
+
+            def check_quote(token):
+                if ";" in str(token):
+                    token = "'%s'" % token
+                return token
+
+            keys = dict((k, check_quote(v)) for k, v in keys.items())
+
+            dsn_connection = "dsn" in keys or (
+                "host" in keys and "database" not in keys
+            )
+            if dsn_connection:
+                connectors = [
+                    "dsn=%s" % (keys.pop("host", "") or keys.pop("dsn", ""))
+                ]
+            else:
+                port = ""
+                if "port" in keys and "port" not in query:
+                    port = ",%d" % int(keys.pop("port"))
+
+                connectors = []
+                driver = keys.pop("driver", self.pyodbc_driver_name)
+                if driver is None:
+                    util.warn(
+                        "No driver name specified; "
+                        "this is expected by PyODBC when using "
+                        "DSN-less connections"
+                    )
+                else:
+                    connectors.append("DRIVER={%s}" % driver)
+
+                connectors.extend(
+                    [
+                        "Server=%s%s" % (keys.pop("host", ""), port),
+                        "Database=%s" % keys.pop("database", ""),
+                    ]
+                )
+
+            user = keys.pop("user", None)
+            if user:
+                connectors.append("UID=%s" % user)
+                connectors.append("PWD=%s" % keys.pop("password", ""))
+            else:
+                connectors.append("Trusted_Connection=Yes")
+
+            # if set to 'Yes', the ODBC layer will try to automagically
+            # convert textual data from your database encoding to your
+            # client encoding.  This should obviously be set to 'No' if
+            # you query a cp1253 encoded database from a latin1 client...
+            if "odbc_autotranslate" in keys:
+                connectors.append(
+                    "AutoTranslate=%s" % keys.pop("odbc_autotranslate")
+                )
+
+            connectors.extend(["%s=%s" % (k, v) for k, v in keys.items()])
+
+        return [[";".join(connectors)], connect_args]
+
+    def is_disconnect(self, e, connection, cursor):
+        if isinstance(e, self.dbapi.ProgrammingError):
+            return "The cursor's connection has been closed." in str(
+                e
+            ) or "Attempt to use a closed connection." in str(e)
+        else:
+            return False
+
+    # def initialize(self, connection):
+    #   super(PyODBCConnector, self).initialize(connection)
+
+    def _dbapi_version(self):
+        if not self.dbapi:
+            return ()
+        return self._parse_dbapi_version(self.dbapi.version)
+
+    def _parse_dbapi_version(self, vers):
+        m = re.match(r"(?:py.*-)?([\d\.]+)(?:-(\w+))?", vers)
+        if not m:
+            return ()
+        vers = tuple([int(x) for x in m.group(1).split(".")])
+        if m.group(2):
+            vers += (m.group(2),)
+        return vers
+
+    def _get_server_version_info(self, connection, allow_chars=True):
+        # NOTE: this function is not reliable, particularly when
+        # freetds is in use.   Implement database-specific server version
+        # queries.
+        dbapi_con = connection.connection
+        version = []
+        r = re.compile(r"[.\-]")
+        for n in r.split(dbapi_con.getinfo(self.dbapi.SQL_DBMS_VER)):
+            try:
+                version.append(int(n))
+            except ValueError:
+                if allow_chars:
+                    version.append(n)
+        return tuple(version)
+
+    def set_isolation_level(self, connection, level):
+        # adjust for ConnectionFairy being present
+        # allows attribute set e.g. "connection.autocommit = True"
+        # to work properly
+        if hasattr(connection, "connection"):
+            connection = connection.connection
+
+        if level == "AUTOCOMMIT":
+            connection.autocommit = True
+        else:
+            connection.autocommit = False
+            super(PyODBCConnector, self).set_isolation_level(connection, level)