cursor

1、连接数据库基础代码 　　使用 pymysql.connect(host, user, passwd, db, port, charset='utf8') 连接数据库 　　使用 cursor() 方法获取操作游标 　　使用 execute(sql) 方法执行SQL语句 　　使用 fetchone() 方法获取一条数据 import pymysql # 打开数据库连接 db = pymysql.connect(host="192.168.120.78", user="test", passwd="Ddc@2019", db="user", port=3306, charset='utf8') # 使用cursor()方法获取操作游标 cursor = db.cursor() # 使用execute()方法执行SQL语句 cursor.execute("SELECT VERSION()") # 使用 fetchone() 方法获取一条数据 data = cursor.fetchone() print("Database version : %s " % data) # 关闭数据库连接 cursor.close() db.close() 2、创建数据库表，使用 execute(sql) 方法执行sql语句 import pymysql # 打开数据库连接 db = pymysql

1. 使用存储过程的优点有： （1）存储过程在服务器端运行，执行速度快。 （2）存储过程执行一次后，其执行规划就驻留在高速缓冲存储器，在以后的操作中，只需从高速缓冲存储器中调用已编译好的二进制代码执行，提高了系统性能。 （3）确保数据库的安全。使用存储过程可以完成所有数据库操作，并可通过编程方式控制上述操作对数据库信息访问的权限。 2.创建存储过程可以使用create procedure语句。 要在MySQL 5.1中创建存储过程，必须具有CREATE routine权限。要想查看数据库中有哪些存储过程，可以使用SHOW PROCEDURE STATUS命令。要查看某个存储过程的具体信息，可使用SHOWCREATE PROCEDURE sp_name命令，其中sp_name是存储过程的名称。 CREATE PROCEDURE的语法格式： CREATE PROCEDURE sp_name ([proc_parameter[,...]]) [characteristic ...] routine_body 其中，proc_parameter的参数如下： [ IN | OUT | INOUT ] param_name type characteristic特征如下： language SQL | [NOT] DETERMINISTIC | { CONTAINS SQL | NO SQL

I have a scrollable timeline that is made from list views. When my mouse is focused over the list view. The cursor is a open hand using the code <ControlTemplate.Triggers> <Trigger Property="IsMouseOver" Value="True"> <Setter Property="Cursor" Value="openHand.cur"/> </Trigger> </ControlTemplate.Triggers> but I was wondering. Is there something I can do if the left mouse button is pressed over the list view. if it is then change the Cursor to a closed hand? Thanks in advance! WPF doesn't have a "IsMouseLeftButtonDown" property, but you can create your own attached property to do this, then

I have an AutoCompleteTextView , which shows dropdown list of suggestions taken from a SQLiteDatabase query. At the moment it uses SimpleCursorAdapter , however there are several problems with it (I have a separate question about the issue here: SimpleCursorAdapter issue - "java.lang.IllegalStateException: trying to requery an already closed cursor" ). Nevertheless, I was advised to look in the direction of CursorLoader and LoaderManager , and I've tried it, yet couldn't make it work . I'd be grateful if someone would guide/recommend/show the right way of migrating my code below to

Suppose I run some query and get a cursor which I want to use to update the entries in the database. What happens if the database is updated while the cursor is not closed? For example, suppose the cursor is pointing at the 1st entry in the result set and I run a query that updates the 10th element. Does the current cursor reflect those changes? The cursor is a copy of the results in memory, so you can modify the database at will. Since it's a copy, it won't reflect any changes - you'd need to requery for that. However, it is absolutely imperative that you close it as soon as possible, to save

SET SERVEROUTPUT ON --必须有，不然显示不出 declare LN_C number(10,0):=0; begin DECLARE LS_STR1 VARCHAR2(200); --循环得到的生产物料编号 CURSOR workunit_cursor IS SELECT ID_CODE FROM MODEL_PRODUCT_RELATION WHERE MODEL_ID='16001RA' GROUP BY ID_CODE; --根据模具编号获取关联的生产物料编号 BEGIN OPEN workunit_cursor; FETCH workunit_cursor INTO LS_STR1; while workunit_cursor%found loop LN_C:=LN_C+1; IF LN_C>35 THEN DBMS_OUTPUT.PUT_LINE('TS:'||LS_STR1); COMMIT; EXIT; END IF; end loop; CLOSE workunit_cursor; END; dbms_output.put_line('tt'); end ; 来源： https://www.cnblogs.com/Bokeyan/p/11990708.html

最近在做一个为网页生成目录的工具 awesome-toc ，该工具提供了以jquery插件的形式使用的代码，也提供了一个基于 Bookmarklet （小书签）的浏览器插件。 小书签需要向网页中注入多个js文件，也就相当于动态加载js文件。在编写这部分代码时候遇到坑了，于是深究了一段时间。 我在这里整理了动态加载js文件的若干思路， 这对于理解异步编程很有用处，而且也适用于Nodejs 。 代码整理在了 https://github.com/someus/how-to-load-dynamic-script 。 硬编码在html源码中的script是如何加载的 如果html中有： <script type="text/javascript" src="1.js"></script> <script type="text/javascript" src="2.js"></script> 那么，浏览器解析到 <script type="text/javascript" src="1.js"></script> 会停止渲染页面，去拉取 1.js （IO操作），等到 1.js 的内容获取到后执行。 1.js执行完毕后，浏览器解析到 <script type="text/javascript" src="2.js"></script> 进行和 1.js 类似的操作。