SQLSERVER一些公用DLL的作用解释 如果你的SQLSERVER安装在C盘的话,下面的路径就是相应SQLSERVER版本的公用DLL的存放路径 SQL2005 C:\Program Files\Microsoft SQL Server\90\SDK\Assemblies\ SQL2008 C:\Program Files\Microsoft SQL Server\100\SDK\Assemb
SQLSERVER一些公用DLL的作用解释
如果你的SQLSERVER安装在C盘的话,下面的路径就是相应SQLSERVER版本的公用DLL的存放路径
SQL2005
C:\Program Files\Microsoft SQL Server\90\SDK\Assemblies\
SQL2008
C:\Program Files\Microsoft SQL Server\100\SDK\Assemblies\
SQL2012
C:\Program Files\Microsoft SQL Server\110\SDK\Assemblies\
可以看到随着SQLSERVER版本的升级,这些公用DLL变得越来越多了,因为SQLSERVER的功能越来越多了
这些DLL有什么用??
这些DLL是供SQLSERVER调用的,因为这些公用DLL在SQLSERVER的很多组件中都有用到,所以SQLSERVER就把这些
DLL放到X:\Program Files\Microsoft SQL Server\X\SDK\Assemblies\文件夹下以供其他SQLSERVER组件调用
例如SSIS、SSAS、数据库引擎还有其他的工具
其实从文件夹路径名我们就可以知道这些DLL的作用:SDK\Assemblies\
大家不知道SDK的含义可以百度一下,不过可能大家比较赖,我就贴出来吧
SDK(Software Development Kit, 即软件开发工具包 )一般是一些被软件工程师用于为特定的软件包、软件框架、硬件平台、操作系统等
建立应用软件的开发工具的集合。
资深程序员一定知道SDK的作用,他就是某个软件提供给我们程序员用来开发的一些接口或者API
本人觉得X:\Program Files\Microsoft SQL Server\X\SDK\Assemblies\文件夹下面的这些DLL不只是提供给SQLSERVER调用的
我们也可以调用这些DLL来开发SQLSERVER数据库的一些相关软件和工具
例子一:
园子里的胡勇大侠就用了下面的两个DLL来做出了: (喷血分享)利用.NET生成数据库表的创建脚本,类似SqlServer编写表的CREATE语句
Microsoft.SqlServer.ConnectionInfo.dll
Microsoft.SqlServer.Management.Sdk.Sfc.dll
例子二:
又例如这个帖子:用c#做了个,sqlServer2005里面那个事件监控器一样的程序,启动问题请帮看看
用Microsoft.SqlServer.ConnectionInfo.dll这个DLL做一个类似于SQL TRACE的工具出来,用来实时查看执行的脚本以及其他信息
例子三:
SQLDoc Sharp(SQLSERVER数据库文档生成工具)
这个工具在codeproject上可以下载:http://www.codeproject.com/Articles/35790/SQLDoc-Sharp
用到了下面的DLL
Microsoft.SqlServer.ConnectionInfo.dll
Microsoft.SqlServer.Management.Sdk.Sfc.dll
Microsoft.SqlServer.Smo.dll
Microsoft.SqlServer.SmoExtended.dll
Microsoft.SqlServer.SqlEnum.dll
公用DLL用什么语言编写?
我们可以发现上面的三个例子中的工具都是用.NET编写的工具,包括SQLDoc Sharp都是用.NET编写的winfrom软件
我们用ILSpy这个软件反编译一下各个SQLSERVER版本的下DLL
将DLL全部拖入去ILSpy里面
SQL2005
SQL2008
SQL2012
SQL2008里面有两个DLL是不能够反编译的,分别是Redist_TSqlLanguageService.dll和Redist_DACFramework.dll
SQL2012里面只有一个DLL是不能够反编译的,是Redist_TSqlLanguageService.dll
不能被反编译的DLL有可能是用C或者C++编写的
我估计这些不能反编译的dll不会提供API功能给用户,只是给SQLSERVER调用的,而且这些DLL对于SQLSERVER的性能有至关重要的作用
所以用C或者C++编写
从上面反编译这些DLL的情况来看,SQLSERVER里面有很大一部分组件或者代码都是用.NET来编写的
除了一些关键功能或者涉及到性能相关的功能组件用C或者C++编写
这里从另一个侧面也可以看出微软对.NET的重用,从SQLSERVER2005开始大量用.NET来编写一些组件代码
从上面三个例子中也可以看出为什麽他们首选.NET来编写这些工具,因为这些公用DLL本来就是.NET DLL(可托管代码)
简单介绍DLL
限于本人的能力有限,本人就只简单介绍比较熟悉的DLL,其他不熟悉的大家可以查MSDN或者百度
我这里会给出一些DLL的资料和查百度、MSDN时候的结果
我这里只介绍SQLSERVER2012的,因为SQLSERVER2012比较齐全,但是某些功能在不同的SQLSERVER版本里会有变化
例如上面第二个例子里:用c#做了个,sqlServer2005里面那个事件监控器一样的程序,启动问题请帮看看
里面说到了TMO这个类在SQL2005版本的SDK里面和SQL2008版本的SDK里面有变化,导致运行时出错
使用Trace Management Object监测和诊断SQL Server(一)
在SQL Server 2005里TMO对象被实现在了Microsoft.SqlServer.ConnectionInfo.dll里,
在SQL Server 2008里TMO对象则被移到了Microsoft.SqlServer.ConnectionInfoExtended.dll里,
但仍然在Microsoft.SqlServer.Management.Trace命名空间里。
类似上面的有变化的API我就不说了,大家开发的时候一定要查清楚MSDN和百度,不要搞错,因为这些SDK的文档比较少
大部分都是E文的,开发起来会比较头痛
废话不说了,开始~
Microsoft.AnalysisServices.DLL
Microsoft.DataWarehouse.Interfaces.DLL
SSAS,数据仓库相关的接口
Kpi 类:http://technet.microsoft.com/zh-cn/library/microsoft.analysisservices.kpi.aspx
http://technet.microsoft.com/zh-cn/magazine/microsoft.datawarehouse.interfaces.idesignertoolwindowservice.gettoolwindow.aspx
Microsoft.ExceptionMessageBox.DLL
SQLSERVER中的各种异常对话框都调用这个DLL
http://technet.microsoft.com/zh-cn/library/microsoft.sqlserver.messagebox.exceptionmessagebox.showcheckbox.aspx
http://social.msdn.microsoft.com/Forums/sqlserver/en-US/138794c0-228f-4d8e-91d8-6ffb704f828c/microsoftexceptionmessageboxdll?forum=sqltools
Microsoft.ReportingServices.Interfaces.DLL
SSRS的相关的接口
http://support.microsoft.com/kb/873267/zh-cn
Microsoft.SqlServer.Smo.DLL
Microsoft.SqlServer.SmoExtended.DLL
Microsoft.SqlServer.Management.Sdk.Sfc.DLL
Microsoft.SqlServer.ConnectionInfo.DLL
Microsoft.SqlServer.ConnectionInfoExtended.DLL
SMO:SQLSERVER管理对象
监控SQLSERVER或者连接SQLSERVER用到
提供SMO对象功能,是SqlServer Management Ojbects的简称,由SQL2005提供的管理对象
只要SQL Server Management Studio能实现的东西,用smo都能实现,因为SQL Server Management Studio就是用smo开发的。
如果你有足够的实力,完全可以开发一个可以藐视SQL Server Management Studio的工具,比如加入智能感知的功能
为了支持 SQL Server 的管理,Integration Services 提供了可以遍历 SQL 管理对象 (SMO) 的对象的枚举器。
例如,包可使用 SMO 枚举器对某个 SQL Server 安装中的 Jobs 集合中的每个作业执行相同的管理功能。
http://support.microsoft.com/kb/956026/zh-cn
http://support.microsoft.com/kb/922214/zh-cn
http://blogs.msdn.com/b/sqlcrd/archive/2009/01/14/trace-management-object-sql-server.aspx
http://msdn.microsoft.com/en-us/library/microsoft.sqlserver.management.smo.aspx
Microsoft.SqlServer.Dts.Design.DLL
Microsoft.SqlServer.DTSPipelineWrap.DLL
Microsoft.SQLServer.DTSRuntimeWrap.DLL
Microsoft.SQLServer.ManagedDTS.DLL
Data Transformation Services (DTS) 数据传输服务相关的DLL
http://bbs.csdn.net/topics/200087190
http://social.msdn.microsoft.com/Forums/sqlserver/zh-CN/916a39c4-c35a-4ba1-8f7a-dde4aadb1675/assembilies-microsoftsqlserverdtspipelinewrap?forum=sqlintegrationservices
http://social.msdn.microsoft.com/Forums/zh-CN/10a94835-8913-40c6-82f5-1d4da37da730/microsoftsqlservermanageddtsdll-not-working?forum=sqlintegrationservices
Microsoft.SqlServer.Management.RegisteredServers.DLL
注册服务器需要用到的DLL
http://connect.microsoft.com/SQLServer/feedback/details/369377/microsoft-sqlserver-management-registeredservers-dll-missing
http://social.msdn.microsoft.com/Forums/sqlserver/zh-CN/7fa941bd-68d3-4ae2-9673-8ab4f7cb2602/microsoftsqlservermanagementregisteredserversdll?forum=sqlsmoanddmo
Microsoft.SqlServer.Management.Utility.DLL
Microsoft.SqlServer.Management.UtilityEnum.DLL
Utility:实用工具类代表一个控制点(UCP)定义的SQL服务器来管理一个或多个的远程SQLSERVER实例的方法和属性
UtilityEnum:该microsoft.sqlserver.management.utility命名空间包含展现SQLSERVER实用工具对象的类
http://msdn.microsoft.com/zh-cn/library/ee242093(v=sql.110).aspx
http://technet.microsoft.com/zh-cn/magazine/microsoft.sqlserver.management.utility(SQL.105).aspx
Microsoft.SqlServer.Management.XEvent.DLL
Microsoft.SqlServer.Management.XEventEnum.DLL
扩展事件相关的DLL
XEvent:在SQLSERVER客户端组件和服务器端组件里创建和使用SQLSERVER扩展事件通过通用对象模型
扩展事件基础设施支持SQL服务器事件数据的相关性
在某些情况下,基础设施也可以用于从数据看应用程序和操作系统里获取相关数据
http://msdn.microsoft.com/zh-cn/library/microsoft.sqlserver.management.xevent.aspx
Microsoft.SqlServer.OlapEnum.DLL
olap系统相关的DLL
Microsoft.SqlServer.Rmo.DLL
Microsoft.SqlServer.Replication.DLL
与复制相关的DLL
RMO:复制管理对象
http://social.msdn.microsoft.com/Forums/sqlserver/zh-CN/fd02b8ad-db40-4785-993f-1adfd00d5a0e/sql-server-2008-r2-replication-management-objects-sqlrmomsi-?forum=sqlreplication
http://social.msdn.microsoft.com/Forums/sqlserver/en-US/07a89afe-50ba-4133-bfa5-e5f9a7a03bcb/rmo-replication-between-sql-server-2005-amd-sql-server-2005-express?forum=sqlreplication
Microsoft.SqlServer.Replication.dll 引发的IIS异常
http://social.msdn.microsoft.com/Forums/zh-CN/ff657b77-8a6e-4602-9903-9c4fca11e3b5/microsoftsqlserverreplicationdll-not-found?forum=sqlreplication
Microsoft.SqlServer.ServiceBrokerEnum.DLL
ServiceBroker相关技术的DLL
http://msdn.microsoft.com/en-us/library/microsoft.sqlserver.management.smo.broker.servicebroker.aspx
Microsoft.SqlServer.SqlWmiManagement.DLL
Microsoft.SqlServer.WmiEnum.DLL
与WMI(Windows Management Instrumentation,Windows 管理规范)相关的DLL
http://support.microsoft.com/kb/967199
打开【SQL Server 配置管理器】提示:无法连接到 WMI 提供程序。您没有权限或者该服务器无法访问。
请注意,您只能使用 SQL Server 配置管理器来管理 SQL Server 2005 服务器。
如何在SQL Server 中添加WMI alert
Microsoft.SqlServer.SString.DLL
SecureString这个类里面有很多字符串相关的C#函数
http://social.msdn.microsoft.com/Forums/sqlserver/zh-CN/22131a3d-f63b-42dc-a211-fdef785886ae/sql-server-2008-management-studio-error-when-connecting-to-server-method-not-found-int32
这个类里面的代码
类:SqlSecureString
<span> 1</span> <span>using</span><span> System; </span><span> 2</span> <span>using</span><span> System.Data.SqlTypes; </span><span> 3</span> <span>using</span><span> System.Globalization; </span><span> 4</span> <span>using</span><span> System.Runtime.InteropServices; </span><span> 5</span> <span>using</span><span> System.Security; </span><span> 6</span> <span>using</span><span> System.Security.Cryptography; </span><span> 7</span> <span>using</span><span> System.Security.Permissions; </span><span> 8</span> <span>using</span><span> System.Text; </span><span> 9</span> <span>using</span><span> System.Xml; </span><span> 10</span> <span>using</span><span> System.Xml.Schema; </span><span> 11</span> <span>using</span><span> System.Xml.Serialization; </span><span> 12</span> <span>namespace</span><span> Microsoft.SqlServer.Common </span><span> 13</span> <span>{ </span><span> 14</span> <span>public</span> <span>sealed</span> <span>class</span> SqlSecureString : ICloneable, IComparable, IComparable<sqlsecurestring><span>, IDisposable, IXmlSerializable </span><span> 15</span> <span> { </span><span> 16</span> <span>private</span><span> SecureString data; </span><span> 17</span> <span>private</span> <span>int</span><span> length; </span><span> 18</span> <span>private</span> <span>static</span><span> SqlSecureString empty; </span><span> 19</span> <span>private</span> <span>static</span> <span>byte</span><span>[] additionalEntropy; </span><span> 20</span> <span>public</span> <span>char</span> <span>this</span>[<span>int</span><span> index] </span><span> 21</span> <span> { </span><span> 22</span> <span>get</span> <span> 23</span> <span> { </span><span> 24</span> <span>return</span> <span>this</span><span>.ToString()[index]; </span><span> 25</span> <span> } </span><span> 26</span> <span> } </span><span> 27</span> <span>public</span> <span>static</span><span> SqlSecureString Empty </span><span> 28</span> <span> { </span><span> 29</span> <span>get</span> <span> 30</span> <span> { </span><span> 31</span> <span>return</span><span> SqlSecureString.empty; </span><span> 32</span> <span> } </span><span> 33</span> <span> } </span><span> 34</span> <span>public</span> <span>int</span><span> Length </span><span> 35</span> <span> { </span><span> 36</span> <span>get</span> <span> 37</span> <span> { </span><span> 38</span> <span>return</span> <span>this</span><span>.length; </span><span> 39</span> <span> } </span><span> 40</span> <span> } </span><span> 41</span> <span>static</span><span> SqlSecureString() </span><span> 42</span> <span> { </span><span> 43</span> SqlSecureString.additionalEntropy = <span>new</span> <span>byte</span><span>[] </span><span> 44</span> <span> { </span><span> 45</span> <span>2</span><span>, </span><span> 46</span> <span>0</span><span>, </span><span> 47</span> <span>0</span><span>, </span><span> 48</span> <span>8</span><span>, </span><span> 49</span> <span>0</span><span>, </span><span> 50</span> <span>4</span> <span> 51</span> <span> }; </span><span> 52</span> SqlSecureString.empty = <span>new</span><span> SqlSecureString(); </span><span> 53</span> <span> } </span><span> 54</span> <span>public</span><span> SqlSecureString() </span><span> 55</span> <span> { </span><span> 56</span> <span>this</span>.data = <span>new</span><span> SecureString(); </span><span> 57</span> <span>this</span>.length = <span>0</span><span>; </span><span> 58</span> <span> } </span><span> 59</span> <span>public</span> SqlSecureString(<span>string</span><span> str) </span><span> 60</span> <span> { </span><span> 61</span> <span>if</span> (str == <span>null</span><span>) </span><span> 62</span> <span> { </span><span> 63</span> <span>throw</span> <span>new</span><span> ArgumentNullException(); </span><span> 64</span> <span> } </span><span> 65</span> <span>this</span>.data = <span>new</span><span> SecureString(); </span><span> 66</span> <span>this</span>.length = <span>0</span><span>; </span><span> 67</span> <span>char</span>[] array =<span> str.ToCharArray(); </span><span> 68</span> <span>for</span> (<span>int</span> i = <span>0</span>; i ) <span> 69</span> <span> { </span><span> 70</span> <span>char</span> c =<span> array[i]; </span><span> 71</span> <span>this</span><span>.data.AppendChar(c); </span><span> 72</span> <span>this</span>.length++<span>; </span><span> 73</span> <span> } </span><span> 74</span> <span> } </span><span> 75</span> <span>public</span><span> SqlSecureString(SecureString secureString) </span><span> 76</span> <span> { </span><span> 77</span> <span>if</span> (secureString == <span>null</span><span>) </span><span> 78</span> <span> { </span><span> 79</span> <span>throw</span> <span>new</span><span> ArgumentNullException(); </span><span> 80</span> <span> } </span><span> 81</span> <span>this</span>.data =<span> secureString.Copy(); </span><span> 82</span> <span>this</span>.length =<span> secureString.Length; </span><span> 83</span> <span> } </span><span> 84</span> <span>public</span> SqlSecureString(IntPtr bstr, <span>int</span><span> length) </span><span> 85</span> <span> { </span><span> 86</span> <span>if</span> (bstr ==<span> IntPtr.Zero) </span><span> 87</span> <span> { </span><span> 88</span> <span>throw</span> <span>new</span><span> ArgumentNullException(); </span><span> 89</span> <span> } </span><span> 90</span> <span>string</span> text =<span> Marshal.PtrToStringAuto(bstr, length); </span><span> 91</span> <span>this</span>.data = <span>new</span><span> SecureString(); </span><span> 92</span> <span>this</span>.length = <span>0</span><span>; </span><span> 93</span> <span>char</span>[] array =<span> text.ToCharArray(); </span><span> 94</span> <span>for</span> (<span>int</span> i = <span>0</span>; i ) <span> 95</span> <span> { </span><span> 96</span> <span>char</span> c =<span> array[i]; </span><span> 97</span> <span>this</span><span>.data.AppendChar(c); </span><span> 98</span> <span>this</span>.length++<span>; </span><span> 99</span> <span> } </span><span>100</span> <span> } </span><span>101</span> <span>public</span> <span>void</span><span> Dispose() </span><span>102</span> <span> { </span><span>103</span> <span>if</span> (<span>this</span>.data != <span>null</span> && <span>this</span> !=<span> SqlSecureString.empty) </span><span>104</span> <span> { </span><span>105</span> <span>this</span><span>.data.Dispose(); </span><span>106</span> <span>this</span>.data = <span>null</span><span>; </span><span>107</span> <span> } </span><span>108</span> <span> } </span><span>109</span> <span>public</span> <span>object</span><span> Clone() </span><span>110</span> <span> { </span><span>111</span> <span>return</span> <span>this</span><span>.Copy(); </span><span>112</span> <span> } </span><span>113</span> <span>public</span> <span>static</span> <span>int</span><span> Compare(SqlSecureString strA, SqlSecureString strB) </span><span>114</span> <span> { </span><span>115</span> <span>return</span> <span>string</span>.Compare((<span>string</span>)strA, (<span>string</span><span>)strB); </span><span>116</span> <span> } </span><span>117</span> <span>public</span> <span>static</span> <span>int</span> Compare(SqlSecureString strA, SqlSecureString strB, <span>bool</span><span> ignoreCase) </span><span>118</span> <span> { </span><span>119</span> <span>return</span> <span>string</span>.Compare((<span>string</span>)strA, (<span>string</span><span>)strB, ignoreCase); </span><span>120</span> <span> } </span><span>121</span> <span>public</span> <span>static</span> <span>int</span><span> Compare(SqlSecureString strA, SqlSecureString strB, StringComparison comparisonType) </span><span>122</span> <span> { </span><span>123</span> <span>return</span> <span>string</span>.Compare((<span>string</span>)strA, (<span>string</span><span>)strB, comparisonType); </span><span>124</span> <span> } </span><span>125</span> <span>public</span> <span>static</span> <span>int</span> Compare(SqlSecureString strA, SqlSecureString strB, <span>bool</span><span> ignoreCase, CultureInfo cultureInfo) </span><span>126</span> <span> { </span><span>127</span> <span>return</span> <span>string</span>.Compare((<span>string</span>)strA, (<span>string</span><span>)strB, ignoreCase, cultureInfo); </span><span>128</span> <span> } </span><span>129</span> <span>public</span> <span>static</span> <span>int</span> Compare(SqlSecureString strA, <span>int</span> indexA, SqlSecureString strB, <span>int</span> indexB, <span>int</span><span> length) </span><span>130</span> <span> { </span><span>131</span> <span>return</span> <span>string</span>.Compare((<span>string</span>)strA, indexA, (<span>string</span><span>)strB, indexB, length); </span><span>132</span> <span> } </span><span>133</span> <span>public</span> <span>static</span> <span>int</span> Compare(SqlSecureString strA, <span>int</span> indexA, SqlSecureString strB, <span>int</span> indexB, <span>int</span> length, <span>bool</span><span> ignoreCase) </span><span>134</span> <span> { </span><span>135</span> <span>return</span> <span>string</span>.Compare((<span>string</span>)strA, indexA, (<span>string</span><span>)strB, indexB, length, ignoreCase); </span><span>136</span> <span> } </span><span>137</span> <span>public</span> <span>static</span> <span>int</span> Compare(SqlSecureString strA, <span>int</span> indexA, SqlSecureString strB, <span>int</span> indexB, <span>int</span><span> length, StringComparison comparisonType) </span><span>138</span> <span> { </span><span>139</span> <span>return</span> <span>string</span>.Compare((<span>string</span>)strA, indexA, (<span>string</span><span>)strB, indexB, length, comparisonType); </span><span>140</span> <span> } </span><span>141</span> <span>public</span> <span>static</span> <span>int</span> Compare(SqlSecureString strA, <span>int</span> indexA, SqlSecureString strB, <span>int</span> indexB, <span>int</span> length, <span>bool</span><span> ignoreCase, CultureInfo cultureInfo) </span><span>142</span> <span> { </span><span>143</span> <span>return</span> <span>string</span>.Compare((<span>string</span>)strA, indexA, (<span>string</span><span>)strB, indexB, length, ignoreCase, cultureInfo); </span><span>144</span> <span> } </span><span>145</span> <span>public</span> <span>static</span> <span>int</span><span> CompareOrdinal(SqlSecureString strA, SqlSecureString strB) </span><span>146</span> <span> { </span><span>147</span> <span>return</span> <span>string</span>.CompareOrdinal((<span>string</span>)strA, (<span>string</span><span>)strB); </span><span>148</span> <span> } </span><span>149</span> <span>public</span> <span>static</span> <span>int</span> CompareOrdinal(SqlSecureString strA, <span>int</span> indexA, SqlSecureString strB, <span>int</span> indexB, <span>int</span><span> length) </span><span>150</span> <span> { </span><span>151</span> <span>return</span> <span>string</span>.CompareOrdinal((<span>string</span>)strA, indexA, (<span>string</span><span>)strB, indexB, length); </span><span>152</span> <span> } </span><span>153</span> <span>public</span> <span>int</span> CompareTo(<span>object</span><span> obj) </span><span>154</span> <span> { </span><span>155</span> <span>int</span> result = <span>1</span><span>; </span><span>156</span> <span>if</span> (obj != <span>null</span><span>) </span><span>157</span> <span> { </span><span>158</span> result = <span>this</span><span>.ToString().CompareTo(obj.ToString()); </span><span>159</span> <span> } </span><span>160</span> <span>return</span><span> result; </span><span>161</span> <span> } </span><span>162</span> <span>public</span> <span>int</span><span> CompareTo(SqlSecureString other) </span><span>163</span> <span> { </span><span>164</span> <span>int</span> result = <span>1</span><span>; </span><span>165</span> <span>if</span> (other != <span>null</span><span>) </span><span>166</span> <span> { </span><span>167</span> result = <span>this</span><span>.ToString().CompareTo(other.ToString()); </span><span>168</span> <span> } </span><span>169</span> <span>return</span><span> result; </span><span>170</span> <span> } </span><span>171</span> <span>public</span> <span>static</span> SqlSecureString Concat(<span>object</span><span> obj) </span><span>172</span> <span> { </span><span>173</span> <span> SqlSecureString result; </span><span>174</span> <span>if</span> (obj != <span>null</span><span>) </span><span>175</span> <span> { </span><span>176</span> result = <span>new</span><span> SqlSecureString(obj.ToString()); </span><span>177</span> <span> } </span><span>178</span> <span>else</span> <span>179</span> <span> { </span><span>180</span> result = <span>new</span><span> SqlSecureString(); </span><span>181</span> <span> } </span><span>182</span> <span>return</span><span> result; </span><span>183</span> <span> } </span><span>184</span> <span>public</span> <span>static</span> SqlSecureString Concat(<span>params</span> <span>object</span><span>[] args) </span><span>185</span> <span> { </span><span>186</span> <span>return</span> <span>new</span> SqlSecureString(<span>string</span><span>.Concat(args)); </span><span>187</span> <span> } </span><span>188</span> <span>public</span> <span>bool</span> Contains(<span>string</span><span> value) </span><span>189</span> <span> { </span><span>190</span> <span>if</span> (value == <span>null</span><span>) </span><span>191</span> <span> { </span><span>192</span> <span>throw</span> <span>new</span><span> ArgumentNullException(); </span><span>193</span> <span> } </span><span>194</span> <span>return</span> <span>this</span><span>.ToString().Contains(value); </span><span>195</span> <span> } </span><span>196</span> <span>public</span> <span>bool</span><span> Contains(SqlSecureString value) </span><span>197</span> <span> { </span><span>198</span> <span>if</span> (value == <span>null</span><span>) </span><span>199</span> <span> { </span><span>200</span> <span>throw</span> <span>new</span><span> ArgumentNullException(); </span><span>201</span> <span> } </span><span>202</span> <span>return</span> <span>this</span><span>.ToString().Contains(value.ToString()); </span><span>203</span> <span> } </span><span>204</span> <span>public</span><span> SqlSecureString Copy() </span><span>205</span> <span> { </span><span>206</span> <span>return</span> <span>new</span> SqlSecureString(<span>this</span><span>.data); </span><span>207</span> <span> } </span><span>208</span> <span>public</span> <span>bool</span><span> EndsWith(SqlSecureString value) </span><span>209</span> <span> { </span><span>210</span> <span>if</span> (value == <span>null</span><span>) </span><span>211</span> <span> { </span><span>212</span> <span>throw</span> <span>new</span><span> ArgumentNullException(); </span><span>213</span> <span> } </span><span>214</span> <span>return</span> <span>this</span><span>.ToString().EndsWith(value.ToString()); </span><span>215</span> <span> } </span><span>216</span> <span>public</span> <span>bool</span> EndsWith(SqlSecureString value, <span>bool</span><span> ignoreCase, CultureInfo cultureInfo) </span><span>217</span> <span> { </span><span>218</span> <span>if</span> (value == <span>null</span><span>) </span><span>219</span> <span> { </span><span>220</span> <span>throw</span> <span>new</span><span> ArgumentNullException(); </span><span>221</span> <span> } </span><span>222</span> <span>return</span> <span>this</span><span>.ToString().EndsWith(value.ToString(), ignoreCase, cultureInfo); </span><span>223</span> <span> } </span><span>224</span> <span>public</span> <span>override</span> <span>bool</span> Equals(<span>object</span><span> obj) </span><span>225</span> <span> { </span><span>226</span> <span>bool</span> result = <span>false</span><span>; </span><span>227</span> <span>if</span> (obj != <span>null</span><span>) </span><span>228</span> <span> { </span><span>229</span> result = <span>this</span><span>.ToString().Equals(obj); </span><span>230</span> <span> } </span><span>231</span> <span>return</span><span> result; </span><span>232</span> <span> } </span><span>233</span> <span>public</span> <span>bool</span><span> Equals(SqlSecureString other) </span><span>234</span> <span> { </span><span>235</span> <span>return</span> <span>this</span> ==<span> other; </span><span>236</span> <span> } </span><span>237</span> <span>public</span> <span>static</span> <span>bool</span><span> Equals(SqlSecureString strA, SqlSecureString strB) </span><span>238</span> <span> { </span><span>239</span> <span>return</span> strA ==<span> strB; </span><span>240</span> <span> } </span><span>241</span> <span>public</span> <span>bool</span><span> Equals(SqlSecureString other, StringComparison comparisonType) </span><span>242</span> <span> { </span><span>243</span> <span>return</span> <span>this</span>.ToString().Equals((<span>string</span><span>)other, comparisonType); </span><span>244</span> <span> } </span><span>245</span> <span>public</span> <span>static</span> <span>bool</span><span> Equals(SqlSecureString strA, SqlSecureString strB, StringComparison comparisonType) </span><span>246</span> <span> { </span><span>247</span> <span>return</span> <span>string</span>.Equals((<span>string</span>)strA, (<span>string</span><span>)strB, comparisonType); </span><span>248</span> <span> } </span><span>249</span> <span>public</span> <span>static</span> SqlSecureString Format(<span>string</span> format, <span>params</span> <span>object</span><span>[] arguments) </span><span>250</span> <span> { </span><span>251</span> <span>return</span> <span>new</span> SqlSecureString(<span>string</span><span>.Format(format, arguments)); </span><span>252</span> <span> } </span><span>253</span> <span>public</span> <span>static</span> SqlSecureString Format(IFormatProvider formatProvider, <span>string</span> format, <span>params</span> <span>object</span><span>[] arguments) </span><span>254</span> <span> { </span><span>255</span> <span>return</span> <span>new</span> SqlSecureString(<span>string</span><span>.Format(formatProvider, format, arguments)); </span><span>256</span> <span> } </span><span>257</span> <span>public</span> <span>override</span> <span>int</span><span> GetHashCode() </span><span>258</span> <span> { </span><span>259</span> <span>return</span> <span>this</span><span>.ToString().GetHashCode(); </span><span>260</span> <span> } </span><span>261</span> <span>public</span> <span>int</span> IndexOf(<span>char</span><span> value) </span><span>262</span> <span> { </span><span>263</span> <span>return</span> <span>this</span><span>.ToString().IndexOf(value); </span><span>264</span> <span> } </span><span>265</span> <span>public</span> <span>int</span> IndexOf(<span>string</span><span> value) </span><span>266</span> <span> { </span><span>267</span> <span>return</span> <span>this</span><span>.ToString().IndexOf(value); </span><span>268</span> <span> } </span><span>269</span> <span>public</span> <span>int</span> IndexOf(<span>char</span> value, <span>int</span><span> startIndex) </span><span>270</span> <span> { </span><span>271</span> <span>return</span> <span>this</span><span>.ToString().IndexOf(value, startIndex); </span><span>272</span> <span> } </span><span>273</span> <span>public</span> <span>int</span> IndexOf(<span>string</span> value, <span>int</span><span> startIndex) </span><span>274</span> <span> { </span><span>275</span> <span>return</span> <span>this</span><span>.ToString().IndexOf(value, startIndex); </span><span>276</span> <span> } </span><span>277</span> <span>public</span> <span>int</span> IndexOf(<span>char</span> value, <span>int</span> startIndex, <span>int</span><span> count) </span><span>278</span> <span> { </span><span>279</span> <span>return</span> <span>this</span><span>.ToString().IndexOf(value, startIndex, count); </span><span>280</span> <span> } </span><span>281</span> <span>public</span> <span>int</span> IndexOf(<span>string</span> value, <span>int</span> startIndex, <span>int</span><span> count) </span><span>282</span> <span> { </span><span>283</span> <span>return</span> <span>this</span><span>.ToString().IndexOf(value, startIndex, count); </span><span>284</span> <span> } </span><span>285</span> <span>public</span> <span>int</span> IndexOfAny(<span>char</span><span>[] anyOf) </span><span>286</span> <span> { </span><span>287</span> <span>return</span> <span>this</span><span>.ToString().IndexOfAny(anyOf); </span><span>288</span> <span> } </span><span>289</span> <span>public</span> <span>int</span> IndexOfAny(<span>char</span>[] anyOf, <span>int</span><span> startIndex) </span><span>290</span> <span> { </span><span>291</span> <span>return</span> <span>this</span><span>.ToString().IndexOfAny(anyOf, startIndex); </span><span>292</span> <span> } </span><span>293</span> <span>public</span> <span>int</span> IndexOfAny(<span>char</span>[] anyOf, <span>int</span> startIndex, <span>int</span><span> count) </span><span>294</span> <span> { </span><span>295</span> <span>return</span> <span>this</span><span>.ToString().IndexOfAny(anyOf, startIndex, count); </span><span>296</span> <span> } </span><span>297</span> <span>public</span> SqlSecureString Insert(<span>int</span><span> startIndex, SqlSecureString value) </span><span>298</span> <span> { </span><span>299</span> <span>if</span> (value == <span>null</span><span>) </span><span>300</span> <span> { </span><span>301</span> <span>throw</span> <span>new</span><span> ArgumentNullException(); </span><span>302</span> <span> } </span><span>303</span> <span>return</span> <span>new</span> SqlSecureString(<span>this</span><span>.ToString().Insert(startIndex, value.ToString())); </span><span>304</span> <span> } </span><span>305</span> <span>public</span> SqlSecureString Insert(<span>int</span> startIndex, <span>string</span><span> value) </span><span>306</span> <span> { </span><span>307</span> <span>if</span> (value == <span>null</span><span>) </span><span>308</span> <span> { </span><span>309</span> <span>throw</span> <span>new</span><span> ArgumentNullException(); </span><span>310</span> <span> } </span><span>311</span> <span>return</span> <span>new</span> SqlSecureString(<span>this</span><span>.ToString().Insert(startIndex, value)); </span><span>312</span> <span> } </span><span>313</span> <span>public</span> <span>static</span> SqlSecureString Join(<span>object</span> separator, <span>object</span><span>[] value) </span><span>314</span> <span> { </span><span>315</span> <span>return</span> SqlSecureString.Join(separator, value, <span>0</span><span>, value.Length); </span><span>316</span> <span> } </span><span>317</span> <span>public</span> <span>static</span> SqlSecureString Join(<span>object</span> separator, <span>object</span>[] value, <span>int</span> startIndex, <span>int</span><span> count) </span><span>318</span> <span> { </span><span>319</span> <span>if</span> (value == <span>null</span><span>) </span><span>320</span> <span> { </span><span>321</span> <span>throw</span> <span>new</span><span> ArgumentNullException(); </span><span>322</span> <span> } </span><span>323</span> <span>if</span> (startIndex 0 || value.Length count) <span>324</span> <span> { </span><span>325</span> <span>throw</span> <span>new</span><span> ArgumentOutOfRangeException(); </span><span>326</span> <span> } </span><span>327</span> StringBuilder stringBuilder = <span>new</span><span> StringBuilder(); </span><span>328</span> <span>if</span> (<span>0</span> count) <span>329</span> <span> { </span><span>330</span> <span>string</span> text = (separator != <span>null</span>) ? separator.ToString() : <span>string</span><span>.Empty; </span><span>331</span> <span>bool</span> flag = text.Length != <span>0</span><span>; </span><span>332</span> <span>int</span> num =<span> startIndex; </span><span>333</span> <span>if</span> (value[num] != <span>null</span><span>) </span><span>334</span> <span> { </span><span>335</span> <span> stringBuilder.Append(value[num].ToString()); </span><span>336</span> <span> } </span><span>337</span> num++<span>; </span><span>338</span> <span>while</span> (num - startIndex count) <span>339</span> <span> { </span><span>340</span> <span>if</span> (value[num] != <span>null</span><span>) </span><span>341</span> <span> { </span><span>342</span> <span>if</span><span> (flag) </span><span>343</span> <span> { </span><span>344</span> <span> stringBuilder.Append(text); </span><span>345</span> <span> } </span><span>346</span> <span> stringBuilder.Append(value[num].ToString()); </span><span>347</span> <span> } </span><span>348</span> num++<span>; </span><span>349</span> <span> } </span><span>350</span> <span> } </span><span>351</span> <span>return</span> <span>new</span><span> SqlSecureString(stringBuilder.ToString()); </span><span>352</span> <span> } </span><span>353</span> <span>public</span> <span>int</span> LastIndexOf(<span>char</span><span> value) </span><span>354</span> <span> { </span><span>355</span> <span>return</span> <span>this</span><span>.ToString().LastIndexOf(value); </span><span>356</span> <span> } </span><span>357</span> <span>public</span> <span>int</span> LastIndexOf(<span>string</span><span> value) </span><span>358</span> <span> { </span><span>359</span> <span>return</span> <span>this</span><span>.ToString().LastIndexOf(value); </span><span>360</span> <span> } </span><span>361</span> <span>public</span> <span>int</span> LastIndexOf(<span>char</span> value, <span>int</span><span> startIndex) </span><span>362</span> <span> { </span><span>363</span> <span>return</span> <span>this</span><span>.ToString().LastIndexOf(value, startIndex); </span><span>364</span> <span> } </span><span>365</span> <span>public</span> <span>int</span> LastIndexOf(<span>string</span> value, <span>int</span><span> startIndex) </span><span>366</span> <span> { </span><span>367</span> <span>return</span> <span>this</span><span>.ToString().LastIndexOf(value, startIndex); </span><span>368</span> <span> } </span><span>369</span> <span>public</span> <span>int</span> LastIndexOf(<span>char</span> value, <span>int</span> startIndex, <span>int</span><span> count) </span><span>370</span> <span> { </span><span>371</span> <span>return</span> <span>this</span><span>.ToString().LastIndexOf(value, startIndex, count); </span><span>372</span> <span> } </span><span>373</span> <span>public</span> <span>int</span> LastIndexOf(<span>string</span> value, <span>int</span> startIndex, <span>int</span><span> count) </span><span>374</span> <span> { </span><span>375</span> <span>return</span> <span>this</span><span>.ToString().LastIndexOf(value, startIndex, count); </span><span>376</span> <span> } </span><span>377</span> <span>public</span> <span>int</span> LastIndexOfAny(<span>char</span><span>[] anyOf) </span><span>378</span> <span> { </span><span>379</span> <span>return</span> <span>this</span><span>.ToString().LastIndexOfAny(anyOf); </span><span>380</span> <span> } </span><span>381</span> <span>public</span> <span>int</span> LastIndexOfAny(<span>char</span>[] anyOf, <span>int</span><span> startIndex) </span><span>382</span> <span> { </span><span>383</span> <span>return</span> <span>this</span><span>.ToString().LastIndexOfAny(anyOf, startIndex); </span><span>384</span> <span> } </span><span>385</span> <span>public</span> <span>int</span> LastIndexOfAny(<span>char</span>[] anyOf, <span>int</span> startIndex, <span>int</span><span> count) </span><span>386</span> <span> { </span><span>387</span> <span>return</span> <span>this</span><span>.ToString().LastIndexOfAny(anyOf, startIndex, count); </span><span>388</span> <span> } </span><span>389</span> <span>public</span> <span>static</span> <span>bool</span> <span>operator</span> ==<span>(SqlSecureString strA, SqlSecureString strB) </span><span>390</span> <span> { </span><span>391</span> <span>bool</span> result = <span>false</span><span>; </span><span>392</span> <span>bool</span> flag = strA == <span>null</span><span>; </span><span>393</span> <span>bool</span> flag2 = strB == <span>null</span><span>; </span><span>394</span> <span>if</span> (flag &&<span> flag2) </span><span>395</span> <span> { </span><span>396</span> result = <span>true</span><span>; </span><span>397</span> <span> } </span><span>398</span> <span>else</span> <span>399</span> <span> { </span><span>400</span> <span>if</span> (!flag && !<span>flag2) </span><span>401</span> <span> { </span><span>402</span> result = (<span>0</span> == <span>string</span><span>.CompareOrdinal(strA.ToString(), strB.ToString())); </span><span>403</span> <span> } </span><span>404</span> <span> } </span><span>405</span> <span>return</span><span> result; </span><span>406</span> <span> } </span><span>407</span> <span>public</span> <span>static</span> <span>bool</span> <span>operator</span> ==(SqlSecureString strA, <span>object</span><span> strB) </span><span>408</span> <span> { </span><span>409</span> <span>bool</span> result = <span>false</span><span>; </span><span>410</span> <span>bool</span> flag = strA == <span>null</span><span>; </span><span>411</span> <span>bool</span> flag2 = strB == <span>null</span><span>; </span><span>412</span> <span>if</span> (flag &&<span> flag2) </span><span>413</span> <span> { </span><span>414</span> result = <span>true</span><span>; </span><span>415</span> <span> } </span><span>416</span> <span>else</span> <span>417</span> <span> { </span><span>418</span> <span>if</span> (!flag && !<span>flag2) </span><span>419</span> <span> { </span><span>420</span> result = (<span>0</span> == <span>string</span><span>.CompareOrdinal(strA.ToString(), strB.ToString())); </span><span>421</span> <span> } </span><span>422</span> <span> } </span><span>423</span> <span>return</span><span> result; </span><span>424</span> <span> } </span><span>425</span> <span>public</span> <span>static</span> <span>bool</span> <span>operator</span> ==(<span>object</span><span> strA, SqlSecureString strB) </span><span>426</span> <span> { </span><span>427</span> <span>bool</span> result = <span>false</span><span>; </span><span>428</span> <span>bool</span> flag = strA == <span>null</span><span>; </span><span>429</span> <span>bool</span> flag2 = strB == <span>null</span><span>; </span><span>430</span> <span>if</span> (flag &&<span> flag2) </span><span>431</span> <span> { </span><span>432</span> result = <span>true</span><span>; </span><span>433</span> <span> } </span><span>434</span> <span>else</span> <span>435</span> <span> { </span><span>436</span> <span>if</span> (!flag && !<span>flag2) </span><span>437</span> <span> { </span><span>438</span> result = (<span>0</span> == <span>string</span><span>.CompareOrdinal(strA.ToString(), strB.ToString())); </span><span>439</span> <span> } </span><span>440</span> <span> } </span><span>441</span> <span>return</span><span> result; </span><span>442</span> <span> } </span><span>443</span> <span>public</span> <span>static</span> <span>bool</span> <span>operator</span> !=<span>(SqlSecureString strA, SqlSecureString strB) </span><span>444</span> <span> { </span><span>445</span> <span>return</span> !(strA ==<span> strB); </span><span>446</span> <span> } </span><span>447</span> <span>public</span> <span>static</span> <span>bool</span> <span>operator</span> !=(SqlSecureString strA, <span>object</span><span> strB) </span><span>448</span> <span> { </span><span>449</span> <span>return</span> !(strA ==<span> strB); </span><span>450</span> <span> } </span><span>451</span> <span>public</span> <span>static</span> <span>bool</span> <span>operator</span> !=(<span>object</span><span> strA, SqlSecureString strB) </span><span>452</span> <span> { </span><span>453</span> <span>return</span> !(strA ==<span> strB); </span><span>454</span> <span> } </span><span>455</span> <span>public</span> <span>static</span> SqlSecureString <span>operator</span> +<span>(SqlSecureString strA, SqlSecureString strB) </span><span>456</span> <span> { </span><span>457</span> <span>return</span> SqlSecureString.Concat(<span>new</span> <span>object</span><span>[] </span><span>458</span> <span> { </span><span>459</span> <span> strA, </span><span>460</span> <span> strB </span><span>461</span> <span> }); </span><span>462</span> <span> } </span><span>463</span> <span>public</span> SqlSecureString PadLeft(<span>int</span><span> totalWidth) </span><span>464</span> <span> { </span><span>465</span> <span>return</span> <span>new</span> SqlSecureString(<span>this</span><span>.ToString().PadLeft(totalWidth)); </span><span>466</span> <span> } </span><span>467</span> <span>public</span> SqlSecureString PadLeft(<span>int</span> totalWidth, <span>char</span><span> paddingChar) </span><span>468</span> <span> { </span><span>469</span> <span>return</span> <span>new</span> SqlSecureString(<span>this</span><span>.ToString().PadLeft(totalWidth, paddingChar)); </span><span>470</span> <span> } </span><span>471</span> <span>public</span> SqlSecureString PadRight(<span>int</span><span> totalWidth) </span><span>472</span> <span> { </span><span>473</span> <span>return</span> <span>new</span> SqlSecureString(<span>this</span><span>.ToString().PadRight(totalWidth)); </span><span>474</span> <span> } </span><span>475</span> <span>public</span> SqlSecureString PadRight(<span>int</span> totalWidth, <span>char</span><span> paddingChar) </span><span>476</span> <span> { </span><span>477</span> <span>return</span> <span>new</span> SqlSecureString(<span>this</span><span>.ToString().PadRight(totalWidth, paddingChar)); </span><span>478</span> <span> } </span><span>479</span> <span>public</span> SqlSecureString Remove(<span>int</span><span> startIndex) </span><span>480</span> <span> { </span><span>481</span> <span>return</span> <span>new</span> SqlSecureString(<span>this</span><span>.ToString().Remove(startIndex)); </span><span>482</span> <span> } </span><span>483</span> <span>public</span> SqlSecureString Remove(<span>int</span> startIndex, <span>int</span><span> count) </span><span>484</span> <span> { </span><span>485</span> <span>return</span> <span>new</span> SqlSecureString(<span>this</span><span>.ToString().Remove(startIndex, count)); </span><span>486</span> <span> } </span><span>487</span> <span>public</span> SqlSecureString Replace(<span>char</span> oldChar, <span>char</span><span> newChar) </span><span>488</span> <span> { </span><span>489</span> <span>return</span> <span>new</span> SqlSecureString(<span>this</span><span>.ToString().Replace(oldChar, newChar)); </span><span>490</span> <span> } </span><span>491</span> <span>public</span><span> SqlSecureString Replace(SqlSecureString oldValue, SqlSecureString newValue) </span><span>492</span> <span> { </span><span>493</span> <span>return</span> <span>new</span> SqlSecureString(<span>this</span><span>.ToString().Replace(oldValue.ToString(), newValue.ToString())); </span><span>494</span> <span> } </span><span>495</span> <span>public</span> SqlSecureString[] Split(<span>char</span><span>[] separator) </span><span>496</span> <span> { </span><span>497</span> <span>return</span> SqlSecureString.StringArrayToSqlSecureStringArray(<span>this</span><span>.ToString().Split(separator)); </span><span>498</span> <span> } </span><span>499</span> <span>public</span> SqlSecureString[] Split(<span>char</span>[] separator, <span>int</span><span> count) </span><span>500</span> <span> { </span><span>501</span> <span>return</span> SqlSecureString.StringArrayToSqlSecureStringArray(<span>this</span><span>.ToString().Split(separator, count)); </span><span>502</span> <span> } </span><span>503</span> <span>public</span> SqlSecureString[] Split(<span>char</span><span>[] separator, StringSplitOptions options) </span><span>504</span> <span> { </span><span>505</span> <span>return</span> SqlSecureString.StringArrayToSqlSecureStringArray(<span>this</span><span>.ToString().Split(separator, options)); </span><span>506</span> <span> } </span><span>507</span> <span>public</span> SqlSecureString[] Split(<span>char</span>[] separator, <span>int</span><span> count, StringSplitOptions options) </span><span>508</span> <span> { </span><span>509</span> <span>return</span> SqlSecureString.StringArrayToSqlSecureStringArray(<span>this</span><span>.ToString().Split(separator, count, options)); </span><span>510</span> <span> } </span><span>511</span> <span>public</span> SqlSecureString[] Split(<span>string</span><span>[] separator, StringSplitOptions options) </span><span>512</span> <span> { </span><span>513</span> <span>return</span> SqlSecureString.StringArrayToSqlSecureStringArray(<span>this</span><span>.ToString().Split(separator, options)); </span><span>514</span> <span> } </span><span>515</span> <span>public</span> SqlSecureString[] Split(<span>string</span>[] separator, <span>int</span><span> count, StringSplitOptions options) </span><span>516</span> <span> { </span><span>517</span> <span>return</span> SqlSecureString.StringArrayToSqlSecureS</sqlsecurestring>

MySQL使用的是GPL许可证。1)GPL许可证允许自由使用、修改和分发MySQL,但修改后的分发需遵循GPL。2)商业许可证可避免公开修改,适合需要保密的商业应用。

选择InnoDB而不是MyISAM的情况包括:1)需要事务支持,2)高并发环境,3)需要高数据一致性;反之,选择MyISAM的情况包括:1)主要是读操作,2)不需要事务支持。InnoDB适合需要高数据一致性和事务处理的应用,如电商平台,而MyISAM适合读密集型且无需事务的应用,如博客系统。

在MySQL中,外键的作用是建立表与表之间的关系,确保数据的一致性和完整性。外键通过引用完整性检查和级联操作维护数据的有效性,使用时需注意性能优化和避免常见错误。

MySQL中有四种主要的索引类型:B-Tree索引、哈希索引、全文索引和空间索引。1.B-Tree索引适用于范围查询、排序和分组,适合在employees表的name列上创建。2.哈希索引适用于等值查询,适合在MEMORY存储引擎的hash_table表的id列上创建。3.全文索引用于文本搜索,适合在articles表的content列上创建。4.空间索引用于地理空间查询,适合在locations表的geom列上创建。

toCreateAnIndexinMysql,usethecReateIndexStatement.1)forasingLecolumn,使用“ createIndexIdx_lastNameEnemployees(lastName); 2)foracompositeIndex,使用“ createIndexIndexIndexIndexIndexDx_nameOmplayees(lastName,firstName,firstName);” 3)forauniqe instex,creationexexexexex,

MySQL和SQLite的主要区别在于设计理念和使用场景:1.MySQL适用于大型应用和企业级解决方案,支持高性能和高并发;2.SQLite适合移动应用和桌面软件,轻量级且易于嵌入。

MySQL中的索引是数据库表中一列或多列的有序结构,用于加速数据检索。1)索引通过减少扫描数据量提升查询速度。2)B-Tree索引利用平衡树结构,适合范围查询和排序。3)创建索引使用CREATEINDEX语句,如CREATEINDEXidx_customer_idONorders(customer_id)。4)复合索引可优化多列查询,如CREATEINDEXidx_customer_orderONorders(customer_id,order_date)。5)使用EXPLAIN分析查询计划,避

在MySQL中使用事务可以确保数据一致性。1)通过STARTTRANSACTION开始事务,执行SQL操作后用COMMIT提交或ROLLBACK回滚。2)使用SAVEPOINT可以设置保存点,允许部分回滚。3)性能优化建议包括缩短事务时间、避免大规模查询和合理使用隔离级别。


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