用jdbc连接数据库时无法找到驱动类怎么办,是什么问题下面是我的代码

jdbc和连接池对于你这个场景来说，都足够，既然用spring管理了，建议还是使用连接池，另外，spring自身没有实现连接池，一般都是对第三方连接池的包装，常见的有C3P0，dbcp以及最近比较流行的boneCP等，这几个配置都差不多太多，以boneCP为例：

<bean id="dataSource" class="comjolboxbonecpBoneCPDataSource"

destroy-method="close">

<property name="driverClass" value="${jdbcdriverClass}" />

<property name="jdbcUrl" value="${jdbcurl}" />

<property name="username" value="${jdbcuser}" />

<property name="password" value="${jdbcpassword}" />

<property name="idleConnectionTestPeriod" value="60" />

<property name="idleMaxAge" value="240" />

<property name="maxConnectionsPerPartition" value="30" />

<property name="minConnectionsPerPartition" value="10" />

<property name="partitionCount" value="2" />

<property name="acquireIncrement" value="5" />

<property name="statementsCacheSize" value="100" />

<property name="releaseHelperThreads" value="3" />

</bean>

<bean id="jdbcTemplate" class="orgspringframeworkjdbccoreJdbcTemplate">

<property name="dataSource" ref="dataSource" />

</bean>

<php

$a = array('one','two');

$b = array('one','two','three','aa','bb');

var_dump(array_diff($b,$a));

var_dump(array_intersect($b,$a));

>

array_diff() 函数返回两个数组的差集数组

array_intersect() 函数返回两个或多个数组的交集数组。

望采纳 Thx

锁的作用，就是把权限归为私有，其它人用不了。你自已把表锁了，自已当然还能用。

1、表级别的锁定是MySQL各存储引擎中最大颗粒度的锁定机制。该锁定机制最大的特点是实现逻辑非常简单，带来的系统负面影响最小。所以获取锁和释放锁的速度很快。由于表级锁一次会将整个表锁定，所以可以很好的避免困扰我们的死锁问题。

2、数据库锁定机制简单来说就是数据库为了保证数据的一致性而使各种共享资源在被并发访问访问变得有序所设计的一种规则。

3、对于任何一种数据库来说都需要有相应的锁定机制，所以MySQL自然也不能例外。

4、MySQL数据库由于其自身架构的特点，存在多种数据存储引擎，每种存储引擎所针对的应用场景特点都不太一样，为了满足各自特定应用场景的需求，每种存储引擎的锁定机制都是为各自所面对的特定场景而优化设计，所以各存储引擎的锁定机制也有较大区别。

5、总的来说，MySQL各存储引擎使用了三种类型（级别）的锁定机制：行级锁定，页级锁定和表级锁定。下面我们先分析一下MySQL这三种锁定的特点和各自的优劣所在。

前面是综合介绍，最后有其他资料的链接

Database security is the system, processes, and procedures that protect a database from unintended activity Unintended activity can be categorized as authenticated misuse, malicious attacks or inadvertent mistakes made by authorized individuals or processes Database security is also a specialty within the broader discipline of computer security

Traditionally databases have been protected from external connections by firewalls or routers on the network perimeter with the database environment existing on the internal network opposed to being located within a demilitarized zone Additional network security devices that detect and alert on malicious database protocol traffic include network intrusion detection systems along with host-based intrusion detection systems

Database security is more critical as networks have become more open

Databases provide many layers and types of information security, typically specified in the data dictionary, including:

Access control

Auditing

Authentication

Encryption

Integrity controls

Database security can begin with the process of creation and publishing of appropriate security standards for the database environment The standards may include specific controls for the various relevant database platforms; a set of best practices that cross over the platforms; and linkages of the standards to higher level polices and governmental regulations

An important procedure when evaluating database security is performing vulnerability assessments against the database A vulnerability assessment attempts to find vulnerability holes that could be used to break into the database Database administrators or information security administrators run vulnerability scans on databases to discover misconfiguration of controls within the layers mentioned above along with known vulnerabilities within the database software The results of the scans should be used to harden the database in order to mitigate the threat of compromise by intruders

A program of continual monitoring for compliance with database security standards is another important task for mission critical database environments Two crucial aspects of database security compliance include patch management and the review and management of permissions (especially public) granted to objects within the database Database objects may include table or other objects listed in the Table link The permissions granted for SQL language commands on objects are considered in this process One should note that compliance monitoring is similar to vulnerability assessment with the key difference that the results of vulnerability assessments generally drive the security standards that lead to the continuous monitoring program Essentially, vulnerability assessment is a preliminary procedure to determine risk where a compliance program is the process of on-going risk assessment

The compliance program should take into consideration any dependencies at the application software level as changes at the database level may have effects on the application software or the application server In direct relation to this topic is that of application security

Application level authentication and authorization mechanisms should be considered as an effective means of providing abstraction from the database layer The primary benefit of abstraction is that of a single sign-on capability across multiple databases and database platforms A Single sign-on system should store the database user's credentials (login id and password), and authenticate to the database on behalf of the user

Another security layer of a more sophisticated nature includes the real-time monitoring of database protocol traffic (SQL) over the network, and/or local monitoring of database activity using software agents Analysis can be performed on the traffic for known exploits or network traffic baselines can be captured overtime to build a normal pattern used for detection of anomalous activity that could be indicative of intrusion These systems can provide a comprehensive Database audit trail in addition to the intrusion detection (and potentially protection) mechanisms

In addition to using external tools for monitoring or auditing, native database audit capabilities are also available for many database platforms The native audit trails are extracted on a regular basis and transferred to a designated security system where the database administrators do not have access This ensures a certain level of segragation of duties that may provide evidence the native audit trails were not modified by authenticed administrators Generally, the native audit trails of databases do not provide sufficient controls to enforce separation of duties; therefore, the network and/or kernel module level host based monitoring capabilities provides a higher degree of confidence for forsenics and preservation of evidence

After an incident occurs, the usage of Database Forensics can be employed to determine the scope

A database security program should include the regular review of permissions granted to individually owned accounts and accounts used by automated processes The accounts used by automated processes should have appropriate controls around password storage such as sufficient encryption and access controls to reduce the risk of compromise For individual accounts, a two-factor authentication system should be considered in a database environment where the risk is commensurate with the expenditure for such an authentication system

In conjunction with a sound database security program, an appropriate disaster recovery program should exist to ensure that service is not interrupted during a security incident or any other incident that results in an outage of the primary database environment An example is that of replication for the primary databases to sites located in different geographical regions

See also

Negative database

External links

>

创建下限非0的数组

使用ArrayCreateInstance()方法:

public static Array CreateInstance(Type elementType, int[] lengths, int[] lowerBounds);

elementType : 要创建的 Array 的 Type。

lengths : 一维数组，它包含要创建的 Array 的每个维度的大小

lowerBounds : 一维数组，它包含要创建的 Array 的每个维度的下限（起始索引）。

再运行下下面的代码理解理解

int[] myArrLen = { 4 };

int[] myArrLow = { 2 };

Array myArrayTwo=ArrayCreateInstance( typeof(String), myArrLen, myArrLow );

myArrayTwoSetValue( "two", 2 );

myArrayTwoSetValue( "three", 3 );

myArrayTwoSetValue( "four", 4 );

PrintIndexAndValues( myArrayTwo );

以上内容从网上搜集而来，我觉得挺好懂的了，记得运行下

myArrayTwoSetValue( "five", 5 );

实验MySQL备份与恢复

一、实验内容：

1、 使用SQL语句导入和导出表数据

2、 使用客户端工具备份还原数据库

3、 使用日志文件恢复数据库

二、实验项目：学生成绩数据库

创建用于学生成绩管理数据库，数据库名为XSCJ中，XSCJ数据库中包括三个表：xs(学生基本情况表)、kc(课程信息表)、xs_cj(成绩表)。。

三、实验步骤：(要求使用语句完成)

1、 使用select into ……outfile导出xs表数据，导出文件名为xstxt，要求每行记录结束回车换行；

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2、 使用create table like语句创建一个与xs表结构相同的表xs1，并使用load data将xstxt的数据完整的导入xs1表中，并查看xs1表；

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3、 使用select into ……outfile导出kc表数据，导出文件名为kc1txt，要求字段之间用逗号隔开，字符型字段值用双引号括起来，每行记录以“->”开头，每行结束回车换行；

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4、 使用create table like语句创建一个与kc表结构相同的表kc1，并使用load data将kc1txt的数据导入kc1表中，要求导入数据是忽略前面3条记录，只导入课程名、课程号、学分三列的数据；

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5、 使用mysqldump备份xscj数据库中的xs表到文件xs2sql中；

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6、 使用mysqldump备份xscj数据库到文件xscj1sql中

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7、 使用mysqldump备份xscj数据库和mysql数据库到文件twodatabasesql中；

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8、 使用mysqldump备份MySQL服务器中的所有数据库到文件allsql中；

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9、 删除xs表，使用mysql命令将文件xs2sql中的数据恢复到xscj数据库中

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10、 删除xscj数据库中的所有表，使用mysql命令将文件xscj1sql中的数据恢复到xscj数据库中；

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11、 将xs表中的数据清空，使用mysqlimport命令将xstxt中的数据导入到xs表中。

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四、实验报告要求

1、 实验报告格式要求

包括内容：标题、实验内容、实验步骤、实验中遇到的问题及解决方案

2、 实验报告内容要求

(1) 标题参看实验指导标题+“实验报告”，如“实验一 MySQL的安装与命令初步实验报告”；

(2) 实验内容与实验指导中相同；

(3) 实验步骤中将自己实验中的每个步骤的命令和 *** 作结果显示界面进行截图完善。

(4) 实验中遇到的问题及解决方案中如实地将自己的问题的解决过程记录出来。

3、 实验报告提交要求

每次实验课结束之后，每个人需要提交实验报告，实验报告命名为：学号姓名

SELECT `id`, `searchTimes` FROM `relationship` WHERE ('word_one' = 'man' AND 'word_two' = 'banana') OR ('word_one' = 'banana' AND 'word_two' = 'man')

--1根据查询出来的结果，看看两个学号的班级列是否相同，相同则在同一个班级

select 学号,班级 from 表的名字

where 学号=‘28‘ or 学号=’29‘

--根据变量法

declare @class_one varchar(50),@class_two varchar(50)

select @class_one=班级 from 表的名字

select @class_two=班级 from 表的名字

if(@class_one=@class_two)

print("29和28号在同一个班级")

else

print("29和28号不在同一个班级")

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