上述Cursor和DictCursor是普通游标,一次性返回所有的数据、进行查询时我们使用fetchall()或者fetchone()方法,都是默认先在内存中缓存所有数据再进行处理,大量的数据会导致内存资源消耗光,内存容易溢出; 而流氏游标是陆陆续续一条一条的返回查询数据,所以这类游标适用于内存低、网络带宽小、数据量大的应用场景中。流...
rows = cursor.fetchall()for row in rows: print(row) Step 7: Close the Connection Post-operation, always ensure that you close the database connection to free up resources. connection.close() Linking pyODBC to IBM Db2 Step 1: Prerequisites Download and install the IBM Db2 ODBC driver, ...
sql ='select * from goods;'print(cs.execute(sql),type(cs.execute(sql))) data = cs.fetchall()# 处理数据foritemindata:print(item) 方式3:Python 还提供了一个contextmanager的装饰器,更进一步简化了上下文管理器的实现方式。通过 yield 将函数分割成两部分,yield 之前的语句在 _ enter_ 方法中执行,y...
The default size is 1. fetchall() Returns the all or remaining rows from the result set. Let’s explain the above methods using an example. #python cursor_method.py #import the library import mysql.connector # creating connection conn = mysql.connector.connect( host="localhost", user="...
rows = cursor.fetchall() #Get column names and print them comma delimited columns = [] for column in cursor.description: columns.append(column[0]) print ', '.join(str(x) for x in columns) #Print data, comma delimited for row in rows: ...
gender varchar, ip_address varchar, cc varchar, country varchar, birthdate varchar, salary float, title varchar, comments ) """ ) cursor.execute("COPY userdata FROM 'userdata1.parquet' (HEADER)") print(cursor.execute('select count(*) from userdata).fetchall()) cursor.close() conn.close(...