调用类，得到类型错误：必须调用未绑定的方法[重复]

Question

我已经查看了 Stackoverflow 上的错误，但我看到的解决方案都没有解决我的问题。我正在尝试为 cx_Oracle 创建一个类，以将我的数据库连接放在一个类中，并在我的数据库实例期间调用它。 我在 C# 中创建了类似的类，但由于某种原因，python 尤其困难。任何帮助表示赞赏。

我利用了这里找到的代码： cx_Oracle and Exception Handling - Good practices?

    import sys
    import os
    import cx_Oracle

    class Oracle(object):

        __db_server = os.getenv("ORACLE_SERVER")
        __db_user = os.getenv("ORACLE_ACCT")
        __db_password = os.getenv("ORACLE_PWD")

        def connect(self):
            """ Connect to the database. """

            try:
                self.db = cx_Oracle.connect(__db_user+'/'+__db_password+'@'+__db_server)
            except cx_Oracle.DatabaseError as e:
                error, = e.args
                if error.code == 1017:
                    print('Please check your credentials.')
                else:
                    print('Database connection error: %s'.format(e))
                # Very important part!
                raise

            # If the database connection succeeded create the cursor
            # we-re going to use.
            self.cursor = db.Cursor()

        def disconnect(self):
            """
            Disconnect from the database. If this fails, for instance
            if the connection instance doesn't exist we don't really care.
            """

            try:
                self.cursor.close()
                self.db.close()
            except cx_Oracle.DatabaseError:
                pass

        def execute(self, sql, bindvars=None, commit=False):
            """
            Execute whatever SQL statements are passed to the method;
            commit if specified. Do not specify fetchall() in here as
            the SQL statement may not be a select.
            bindvars is a dictionary of variables you pass to execute.
            """

            try:
                self.cursor.execute(sql, bindvars)
            except cx_Oracle.DatabaseError as e:
                error, = e.args
                if error.code == 955:
                    print('Table already exists')
                elif error.code == 1031:
                    print("Insufficient privileges")
                print(error.code)
                print(error.message)
                print(error.context)

                # Raise the exception.
                raise

            # Only commit if it-s necessary.
            if commit:
                self.db.commit()

        def select(self, sql, commit=False):        
            bindvars=None
            result = None
            try:
                self.cursor.execute(sql, bindvars)
                result = self.cursor.fetchall()
            except cx_Oracle.DatabaseError as e:
                error, = e.args
                print "Database Error: failed with error code:%d - %s" % (error.code, error.message)
                raise
            if commit:
                self.db.commit()
            return result

        def commit(self):
            try:
                self.db.commit()
            except cx_Oracle.DatabaseError as e:
                error, = e.args
                print "Database Commit failed with error code:%d - %s" % (error.code, error.message)
                raise

        def rollback(self):
            try:
                self.db.rollback()
            except cx_Oracle.DatabaseError as e:
                error, = e.args
                print "Database Rollback failed with error code:%d - %s" %(error.code, error.message)
                raise

这是我的调用例程

    import sys
    import os
    #import cx_Oracle
    from Oracle import Oracle

    def main():
        oracle = Oracle.connect()
        query = """SELECT DISTINCT NAME FROM MyTable"""
        data = oracle.select(query)
        for row in data:
            print row
        oracle.disconnect()

    ### MAIN
    if __name__ == '__main__':
        main()

关于相关说明：我似乎无法让 Python 找到我的 Oracle.py 类，除非它与调用函数位于同一目录中。

艾伦

Answer 1

您必须创建类的实例才能使用它：

orcl = Oracle()
orcl.connect()
...