开发小型软件过程中,为了节约开发时间,数据库操作的代码自己都封装了。上篇介绍了SqlCeHelper这个关于操作本地数据库sdf的例子。现在介绍一下在Sqlserver中的代码。 因为Sqlserver数据库有多种登录方式,所以在构造函数中: #region [构造函数] /// summar
开发小型软件过程中,为了节约开发时间,数据库操作的代码自己都封装了。上篇介绍了SqlCeHelper这个关于操作本地数据库sdf的例子。现在介绍一下在Sqlserver中的代码。
因为Sqlserver数据库有多种登录方式,所以在构造函数中:
<span>#region</span>[构造函数] <span>///</span> <span><summary></summary></span> <span>///</span><span> 构造函数,初始化 </span><span>///</span> <span></span> <span>///</span> <span><param name="ConStr"></span><span>正确的数据库连接字符串</span><span></span> <span>///</span> <span><param name="TimeOut"></span><span>超时时间</span><span></span> <span>public</span> SqlServerHelper(<span>string</span> ConStr, <span>int</span><span> TimeOut) { ConnectString </span>=<span> ConStr; connect </span>= <span>new</span><span> SqlConnection(ConnectString); CommandTimeOut </span>=<span> TimeOut; } </span><span>///</span> <span><summary></summary></span> <span>///</span><span> 构造函数,初始化 </span><span>///</span> <span></span> <span>///</span> <span><param name="ConStr"></span><span>正确的数据库连接字符串</span><span></span> <span>public</span> SqlServerHelper(<span>string</span><span> ConStr) { ConnectString </span>=<span> ConStr; connect </span>= <span>new</span><span> SqlConnection(ConnectString); CommandTimeOut </span>= <span>30</span><span>; } </span><span>///</span> <span><summary></summary></span> <span>///</span><span> 构造函数,初始化 </span><span>///</span> <span></span> <span>///</span> <span><param name="DataServer"></span><span>数据库服务器名称或地址</span><span></span> <span>///</span> <span><param name="DataBase"></span><span>访问的数据库</span><span></span> <span>///</span> <span><param name="UserID"></span><span>用户名</span><span></span> <span>///</span> <span><param name="Pwd"></span><span>密码</span><span></span> <span>///</span> <span><param name="TimeOut"></span><span>超时时间</span><span></span> <span>public</span> SqlServerHelper(<span>string</span> DataServer, <span>string</span> DataBase, <span>string</span> UserID, <span>string</span> Pwd,<span>int</span><span> TimeOut) { ConnectString </span>= <span>string</span>.Format(<span>"</span><span>Data Source={0};Initial Catalog={1};User ID={2};pwd={3}</span><span>"</span><span>, DataServer, DataBase, UserID, Pwd); connect </span>= <span>new</span><span> SqlConnection(ConnectString); CommandTimeOut </span>=<span> TimeOut; } </span><span>///</span> <span><summary></summary></span> <span>///</span><span> 构造函数,初始化 </span><span>///</span> <span></span> <span>///</span> <span><param name="DataServer"></span><span>数据库服务器名称或地址</span><span></span> <span>///</span> <span><param name="DataBase"></span><span>访问的数据库</span><span></span> <span>///</span> <span><param name="UserID"></span><span>用户名</span><span></span> <span>///</span> <span><param name="Pwd"></span><span>密码</span><span></span> <span>public</span> SqlServerHelper(<span>string</span> DataServer, <span>string</span> DataBase, <span>string</span> UserID, <span>string</span><span> Pwd) { ConnectString </span>= <span>string</span>.Format(<span>"</span><span>Data Source={0};Initial Catalog={1};User ID={2};pwd={3}</span><span>"</span><span>, DataServer, DataBase, UserID, Pwd); connect </span>= <span>new</span><span> SqlConnection(ConnectString); CommandTimeOut </span>= <span>30</span><span>; } </span><span>///</span> <span><summary></summary></span> <span>///</span><span> 构造函数,初始化 </span><span>///</span> <span></span> <span>///</span> <span><param name="database"></span><span>访问的数据库</span><span></span> <span>///</span> <span><param name="isLocal"></span><span>是否为本地数据库?若False,则抛出异常</span><span></span> <span>///</span> <span><param name="TimeOut"></span><span>超时时间</span><span></span> <span>public</span> SqlServerHelper(<span>string</span> database, <span>bool</span> isLocal,<span>int</span><span> TimeOut) { </span><span>if</span> (!<span>isLocal) { </span><span>throw</span> (<span>new</span> Exception(<span>"</span><span>不在本地而是用了本地数据库访问方式,导致异常,请修改isLocal的值为True。</span><span>"</span><span>)); } connectstring </span>= <span>string</span>.Format(<span>"</span><span>Data Source=127.0.0.1;Initial Catalog={0};Integrated Security=True</span><span>"</span><span>, database); connect </span>= <span>new</span><span> SqlConnection(ConnectString); CommandTimeOut </span>=<span> TimeOut; } </span><span>///</span> <span><summary></summary></span> <span>///</span><span> 构造函数,初始化 </span><span>///</span> <span></span> <span>///</span> <span><param name="database"></span><span>访问的数据库</span><span></span> <span>///</span> <span><param name="isLocal"></span><span>是否为本地数据库?若False,则抛出异常</span><span></span> <span>public</span> SqlServerHelper(<span>string</span> database, <span>bool</span><span> isLocal) { </span><span>if</span> (!<span>isLocal) { </span><span>throw</span> (<span>new</span> Exception(<span>"</span><span>不在本地而是用了本地数据库访问方式,导致异常,请修改isLocal的值为True。</span><span>"</span><span>)); } connectstring </span>= <span>string</span>.Format(<span>"</span><span>Data Source=127.0.0.1;Initial Catalog={0};Integrated Security=True</span><span>"</span><span>, database); connect </span>= <span>new</span><span> SqlConnection(ConnectString); CommandTimeOut </span>= <span>30</span><span>; } </span><span>#endregion</span>
这样,可以方便地构造出自己的连接字符串。
同时这里用到几个比较有用的有关数据库服务器及数据库结构的函数。比如查询局域网中所有数据库实例,获取目标实例所有数据库,获取指定数据库的所有表,获取指定表所有行:
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<span>#region</span> 供使用API方式时使用<span> [DllImport(</span><span>"</span><span>odbc32.dll</span><span>"</span><span>)] </span><span>private</span> <span>static</span> <span>extern</span> <span>short</span> SQLAllocHandle(<span>short</span> hType, IntPtr inputHandle, <span>out</span><span> IntPtr outputHandle); [DllImport(</span><span>"</span><span>odbc32.dll</span><span>"</span><span>)] </span><span>private</span> <span>static</span> <span>extern</span> <span>short</span> SQLSetEnvAttr(IntPtr henv, <span>int</span> attribute, IntPtr valuePtr, <span>int</span><span> strLength); [DllImport(</span><span>"</span><span>odbc32.dll</span><span>"</span><span>)] </span><span>private</span> <span>static</span> <span>extern</span> <span>short</span> SQLFreeHandle(<span>short</span><span> hType, IntPtr handle); [DllImport(</span><span>"</span><span>odbc32.dll</span><span>"</span>, CharSet =<span> System.Runtime.InteropServices.CharSet.Ansi)] </span><span>private</span> <span>static</span> <span>extern</span> <span>short</span><span> SQLBrowseConnect(IntPtr hconn, System.Text.StringBuilder inString, </span><span>short</span> inStringLength, System.Text.StringBuilder outString, <span>short</span><span> outStringLength, </span><span>out</span> <span>short</span><span> outLengthNeeded); </span><span>private</span> <span>const</span> <span>short</span> SQL_HANDLE_ENV = <span>1</span><span>; </span><span>private</span> <span>const</span> <span>short</span> SQL_HANDLE_DBC = <span>2</span><span>; </span><span>private</span> <span>const</span> <span>int</span> SQL_ATTR_ODBC_VERSION = <span>200</span><span>; </span><span>private</span> <span>const</span> <span>int</span> SQL_OV_ODBC3 = <span>3</span><span>; </span><span>private</span> <span>const</span> <span>short</span> SQL_SUCCESS = <span>0</span><span>; </span><span>private</span> <span>const</span> <span>short</span> SQL_NEED_DATA = <span>99</span><span>; </span><span>private</span> <span>const</span> <span>short</span> DEFAULT_RESULT_SIZE = <span>1024</span><span>; </span><span>private</span> <span>const</span> <span>string</span> SQL_DRIVER_STR = <span>"</span><span>DRIVER=SQL SERVER</span><span>"</span><span>; </span><span>#endregion</span> <span>///</span> <span><summary></summary></span> <span>///</span><span> 获取网内的数据库服务器名称(API方式) </span><span>///</span> <span></span> <span>///</span> <span><returns></returns></span><span>服务器名称数组</span><span></span> <span>public</span> <span>static</span> <span>string</span><span>[] GetServers() { </span><span>string</span> list = <span>string</span><span>.Empty; IntPtr henv </span>=<span> IntPtr.Zero; IntPtr hconn </span>=<span> IntPtr.Zero; System.Text.StringBuilder inString </span>= <span>new</span><span> System.Text.StringBuilder(SQL_DRIVER_STR); System.Text.StringBuilder outString </span>= <span>new</span><span> System.Text.StringBuilder(DEFAULT_RESULT_SIZE); </span><span>short</span> inStringLength = (<span>short</span><span>)inString.Length; </span><span>short</span> lenNeeded = <span>0</span><span>; </span><span>try</span><span> { </span><span>if</span> (SQL_SUCCESS == SQLAllocHandle(SQL_HANDLE_ENV, henv, <span>out</span><span> henv)) { </span><span>if</span> (SQL_SUCCESS == SQLSetEnvAttr(henv, SQL_ATTR_ODBC_VERSION, (IntPtr)SQL_OV_ODBC3, <span>0</span><span>)) { </span><span>if</span> (SQL_SUCCESS == SQLAllocHandle(SQL_HANDLE_DBC, henv, <span>out</span><span> hconn)) { </span><span>if</span> (SQL_NEED_DATA ==<span> SQLBrowseConnect(hconn, inString, inStringLength, outString, DEFAULT_RESULT_SIZE, </span><span>out</span><span> lenNeeded)) { </span><span>if</span> (DEFAULT_RESULT_SIZE lenNeeded) { outString.Capacity =<span> lenNeeded; </span><span>if</span> (SQL_NEED_DATA !=<span> SQLBrowseConnect(hconn, inString, inStringLength, outString, lenNeeded, </span><span>out</span><span> lenNeeded)) { </span><span>throw</span> <span>new</span> ApplicationException(<span>"</span><span>Unabled to aquire SQL Servers from ODBC driver.</span><span>"</span><span>); } } list </span>=<span> outString.ToString(); </span><span>int</span> start = list.IndexOf(<span>"</span><span>{</span><span>"</span>) + <span>1</span><span>; </span><span>int</span> len = list.IndexOf(<span>"</span><span>}</span><span>"</span>) -<span> start; </span><span>if</span> ((start > <span>0</span>) && (len > <span>0</span><span>)) { list </span>=<span> list.Substring(start, len); } </span><span>else</span><span> { list </span>= <span>string</span><span>.Empty; } } } } } } </span><span>catch</span><span> { list </span>= <span>string</span><span>.Empty; } </span><span>finally</span><span> { </span><span>if</span> (hconn !=<span> IntPtr.Zero) { SQLFreeHandle(SQL_HANDLE_DBC, hconn); } </span><span>if</span> (henv !=<span> IntPtr.Zero) { SQLFreeHandle(SQL_HANDLE_ENV, hconn); } } </span><span>string</span>[] array = <span>null</span><span>; </span><span>if</span> (list.Length > <span>0</span><span>) { array </span>= list.Split(<span>'</span><span>,</span><span>'</span><span>); } </span><span>return</span><span> array; } </span><span>///</span> <span><summary></summary></span> <span>///</span><span> 获取网内的数据库服务器名称(qlClientFactory方式) </span><span>///</span> <span></span> <span>///</span> <span><returns></returns></span><span>服务器名称数组</span><span></span> <span>public</span> <span>static</span> <span>string</span><span>[] GetServersBySqlClientFactory() { DataTable dataSources </span>=<span> SqlClientFactory.Instance.CreateDataSourceEnumerator().GetDataSources(); DataColumn column2 </span>= dataSources.Columns[<span>"</span><span>ServerName</span><span>"</span><span>]; DataColumn column </span>= dataSources.Columns[<span>"</span><span>InstanceName</span><span>"</span><span>]; DataRowCollection rows </span>=<span> dataSources.Rows; </span><span>string</span>[] array = <span>new</span> <span>string</span><span>[rows.Count]; </span><span>for</span> (<span>int</span> i = <span>0</span>; i ) { <span>string</span> str2 = rows[i][column2] <span>as</span> <span>string</span><span>; </span><span>string</span> str = rows[i][column] <span>as</span> <span>string</span><span>; </span><span>if</span> (((str == <span>null</span>) || (str.Length == <span>0</span>)) || (<span>"</span><span>MSSQLSERVER</span><span>"</span> ==<span> str)) { array[i] </span>=<span> str2; } </span><span>else</span><span> { array[i] </span>= str2 + <span>@"</span><span>\</span><span>"</span> +<span> str; } } Array.Sort</span>string><span>(array); </span><span>return</span><span> array; } </span><span>///</span> <span><summary></summary></span> <span>///</span><span> 根据不带数据库的连接字符串,遍历查找出所有数据库实例 </span><span>///</span> <span></span> <span>///</span> <span><returns></returns></span><span>指定服务器的所有数据库</span><span></span> <span>public</span> <span>string</span><span>[] GetDataBases() { List</span>string> list = <span>new</span> Liststring><span>(); SqlConnection sqlConnection </span>= <span>new</span><span> SqlConnection(ConnectString); </span><span>string</span><span>[] result; </span><span>try</span><span> { sqlConnection.Open(); SqlCommand sqlCommand </span>= <span>new</span> SqlCommand(<span>"</span><span>select name AS 数据库 from master..sysdatabases</span><span>"</span><span>, sqlConnection); SqlDataReader sqlDataReader </span>=<span> sqlCommand.ExecuteReader(); </span><span>while</span><span> (sqlDataReader.Read()) { list.Add(sqlDataReader.GetString(</span><span>0</span><span>)); } sqlDataReader.Close(); </span><span>string</span>[] array = <span>new</span> <span>string</span><span>[] { </span><span>"</span><span>master</span><span>"</span><span>, </span><span>"</span><span>tempdb</span><span>"</span><span>, </span><span>"</span><span>model</span><span>"</span><span>, </span><span>"</span><span>msdb</span><span>"</span><span> }; </span><span>string</span>[] array2 =<span> array; </span><span>for</span> (<span>int</span> i = <span>0</span>; i ) { <span>string</span> item =<span> array2[i]; </span><span>try</span><span> { list.Remove(item); } </span><span>catch</span><span> { } } result </span>=<span> list.ToArray(); } </span><span>catch</span><span> { result </span>=<span> list.ToArray(); } </span><span>finally</span><span> { sqlConnection.Close(); } </span><span>return</span><span> result; } </span><span>///</span> <span><summary></summary></span> <span>///</span><span> 获取SqlServer指定数据库的所有表 </span><span>///</span> <span></span> <span>///</span> <span><returns></returns></span><span>表集合,出错则产生异常</span><span></span> <span>public</span> <span>string</span><span>[] GetTables() { </span><span>string</span> sql = <span>"</span><span>select object_name (id) from sysobjects where xtype = 'u' and objectproperty (id,'IsMSShipped') = 0</span><span>"</span><span>; DataTable dt </span>=<span> ReturnDataTable(sql); List</span>string> Ls = <span>new</span> Liststring><span>(); </span><span>for</span> (<span>int</span> i = <span>0</span>; i ) { Ls.Add(dt.Rows[i][<span>0</span><span>].ToString()); } </span><span>return</span><span> Ls.ToArray(); } </span><span>///</span> <span><summary></summary></span> <span>///</span><span> 获取指定表的所有列 </span><span>///</span> <span></span> <span>///</span> <span><param name="TableName"></span><span>表名</span><span></span> <span>///</span> <span><returns></returns></span><span>列集合,出错则产生异常</span><span></span> <span>public</span> <span>string</span>[] GetColumns(<span>string</span><span> TableName) { </span><span>string</span> sql = <span>string</span>.Format(<span>"</span><span>select name from syscolumns where id=object_id('{0}')</span><span>"</span><span>,TableName); </span><span>try</span><span> { List</span>string> Ls = <span>new</span> Liststring><span>(); DataTable dt </span>=<span> ReturnDataTable(sql); </span><span>for</span> (<span>int</span> i = <span>0</span>; i ) { Ls.Add(dt.Rows[i][<span>0</span><span>].ToString()); } </span><span>return</span><span> Ls.ToArray(); } </span><span>catch</span><span> { </span><span>throw</span><span>; } }</span>
接下来就是许多比较常用的增删改查的操作了。就不分开写了。
为了查看方便,贴出自己所有代码:
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using System; using System.Collections.Generic; using System.Data.SqlClient; using System.Data; using System.Collections; using System.Runtime.InteropServices; namespace MyTool.DataBase { ////// SQL Server 数据库的操作类库。代码原创。 /// public class SqlServerHelper { #region[字段] private string connectstring = "Data Source=127.0.0.1;Initial Catalog=AdventureWorksDW;Integrated Security=True"; SqlConnection connect = null; SqlCommand command = null; private int CommandTimeOut = 30; #endregion #region[属性] /// /// 数据库连接字符串 /// public string ConnectString { get { return connectstring; } set { connectstring = value; } } #endregion <span>#region</span>[构造函数] <span>///</span> <span><summary></summary></span> <span>///</span><span> 构造函数,初始化 </span><span>///</span> <span></span> <span>///</span> <span><param name="ConStr"></span><span>正确的数据库连接字符串</span><span></span> <span>///</span> <span><param name="TimeOut"></span><span>超时时间</span><span></span> <span>public</span> SqlServerHelper(<span>string</span> ConStr, <span>int</span><span> TimeOut) { ConnectString </span>=<span> ConStr; connect </span>= <span>new</span><span> SqlConnection(ConnectString); CommandTimeOut </span>=<span> TimeOut; } </span><span>///</span> <span><summary></summary></span> <span>///</span><span> 构造函数,初始化 </span><span>///</span> <span></span> <span>///</span> <span><param name="ConStr"></span><span>正确的数据库连接字符串</span><span></span> <span>public</span> SqlServerHelper(<span>string</span><span> ConStr) { ConnectString </span>=<span> ConStr; connect </span>= <span>new</span><span> SqlConnection(ConnectString); CommandTimeOut </span>= <span>30</span><span>; } </span><span>///</span> <span><summary></summary></span> <span>///</span><span> 构造函数,初始化 </span><span>///</span> <span></span> <span>///</span> <span><param name="DataServer"></span><span>数据库服务器名称或地址</span><span></span> <span>///</span> <span><param name="DataBase"></span><span>访问的数据库</span><span></span> <span>///</span> <span><param name="UserID"></span><span>用户名</span><span></span> <span>///</span> <span><param name="Pwd"></span><span>密码</span><span></span> <span>///</span> <span><param name="TimeOut"></span><span>超时时间</span><span></span> <span>public</span> SqlServerHelper(<span>string</span> DataServer, <span>string</span> DataBase, <span>string</span> UserID, <span>string</span> Pwd,<span>int</span><span> TimeOut) { ConnectString </span>= <span>string</span>.Format(<span>"</span><span>Data Source={0};Initial Catalog={1};User ID={2};pwd={3}</span><span>"</span><span>, DataServer, DataBase, UserID, Pwd); connect </span>= <span>new</span><span> SqlConnection(ConnectString); CommandTimeOut </span>=<span> TimeOut; } </span><span>///</span> <span><summary></summary></span> <span>///</span><span> 构造函数,初始化 </span><span>///</span> <span></span> <span>///</span> <span><param name="DataServer"></span><span>数据库服务器名称或地址</span><span></span> <span>///</span> <span><param name="DataBase"></span><span>访问的数据库</span><span></span> <span>///</span> <span><param name="UserID"></span><span>用户名</span><span></span> <span>///</span> <span><param name="Pwd"></span><span>密码</span><span></span> <span>public</span> SqlServerHelper(<span>string</span> DataServer, <span>string</span> DataBase, <span>string</span> UserID, <span>string</span><span> Pwd) { ConnectString </span>= <span>string</span>.Format(<span>"</span><span>Data Source={0};Initial Catalog={1};User ID={2};pwd={3}</span><span>"</span><span>, DataServer, DataBase, UserID, Pwd); connect </span>= <span>new</span><span> SqlConnection(ConnectString); CommandTimeOut </span>= <span>30</span><span>; } </span><span>///</span> <span><summary></summary></span> <span>///</span><span> 构造函数,初始化 </span><span>///</span> <span></span> <span>///</span> <span><param name="database"></span><span>访问的数据库</span><span></span> <span>///</span> <span><param name="isLocal"></span><span>是否为本地数据库?若False,则抛出异常</span><span></span> <span>///</span> <span><param name="TimeOut"></span><span>超时时间</span><span></span> <span>public</span> SqlServerHelper(<span>string</span> database, <span>bool</span> isLocal,<span>int</span><span> TimeOut) { </span><span>if</span> (!<span>isLocal) { </span><span>throw</span> (<span>new</span> Exception(<span>"</span><span>不在本地而是用了本地数据库访问方式,导致异常,请修改isLocal的值为True。</span><span>"</span><span>)); } connectstring </span>= <span>string</span>.Format(<span>"</span><span>Data Source=127.0.0.1;Initial Catalog={0};Integrated Security=True</span><span>"</span><span>, database); connect </span>= <span>new</span><span> SqlConnection(ConnectString); CommandTimeOut </span>=<span> TimeOut; } </span><span>///</span> <span><summary></summary></span> <span>///</span><span> 构造函数,初始化 </span><span>///</span> <span></span> <span>///</span> <span><param name="database"></span><span>访问的数据库</span><span></span> <span>///</span> <span><param name="isLocal"></span><span>是否为本地数据库?若False,则抛出异常</span><span></span> <span>public</span> SqlServerHelper(<span>string</span> database, <span>bool</span><span> isLocal) { </span><span>if</span> (!<span>isLocal) { </span><span>throw</span> (<span>new</span> Exception(<span>"</span><span>不在本地而是用了本地数据库访问方式,导致异常,请修改isLocal的值为True。</span><span>"</span><span>)); } connectstring </span>= <span>string</span>.Format(<span>"</span><span>Data Source=127.0.0.1;Initial Catalog={0};Integrated Security=True</span><span>"</span><span>, database); connect </span>= <span>new</span><span> SqlConnection(ConnectString); CommandTimeOut </span>= <span>30</span><span>; } </span><span>#endregion</span> #region[私有函数] private void Open() { try { if (connect.State != System.Data.ConnectionState.Open) { connect.Open(); } } catch (Exception ex) { throw (new Exception(ex.Message)); } } private void Close() { try { if (connect.State != System.Data.ConnectionState.Closed) { connect.Close(); } } catch (Exception ex) { throw (new Exception(ex.Message)); } } #endregion /// /// 测试是否能够连通 /// /// 布尔值 public bool ConnectTest() { try { connect.Open(); } catch { connect.Close(); return false; } return true; } /// /// 执行无返回的Sql语句,如插入,删除,更新 /// /// SQL语句 /// 受影响的条数 public int ExecuteNonQuery(string sqlstr) { try { Open(); command = new SqlCommand(sqlstr, connect); int num = command.ExecuteNonQuery(); command.Parameters.Clear(); Close(); return num; } catch { throw; } } /// /// 执行查询语句,返回DataSet /// /// Sql /// DataSet数据集 public DataSet ReturnDataSet(string sqlstr) { DataSet ds = new DataSet(); try { Open(); SqlDataAdapter adapter = new SqlDataAdapter(sqlstr, connect); adapter.Fill(ds, "Obj"); } catch (Exception) { throw; } return ds; } /// /// 执行查询语句,返回DataTable /// /// Sqk /// DataTable数据表 public DataTable ReturnDataTable(string sqlstr) { return ReturnDataSet(sqlstr).Tables[0]; } /// /// 执行查询语句,返回DataReader /// /// Sql /// DataReader public SqlDataReader ReturnDataReader(string sqlstr) { try { Open(); command = new SqlCommand(sqlstr, connect); SqlDataReader myReader = command.ExecuteReader(); command.Parameters.Clear(); Close(); return myReader; } catch (System.Data.SqlClient.SqlException e) { throw new Exception(e.Message); } } /// /// 执行事务 /// /// public void ExecuteSqlTran(ArrayList SQLStringList) { Open(); command = new SqlCommand(); command.Connection = connect; SqlTransaction tx = connect.BeginTransaction(); command.Transaction = tx; try { for (int n = 0; n ) { string strsql = SQLStringList[n].ToString(); if (strsql.Trim().Length > 1) { command.CommandText = strsql; command.ExecuteNonQuery(); } } tx.Commit(); } catch (Exception) { tx.Rollback(); throw; } } #region 供使用API方式时使用 [DllImport("odbc32.dll")] private static extern short SQLAllocHandle(short hType, IntPtr inputHandle, out IntPtr outputHandle); [DllImport("odbc32.dll")] private static extern short SQLSetEnvAttr(IntPtr henv, int attribute, IntPtr valuePtr, int strLength); [DllImport("odbc32.dll")] private static extern short SQLFreeHandle(short hType, IntPtr handle); [DllImport("odbc32.dll", CharSet = System.Runtime.InteropServices.CharSet.Ansi)] private static extern short SQLBrowseConnect(IntPtr hconn, System.Text.StringBuilder inString, short inStringLength, System.Text.StringBuilder outString, short outStringLength, out short outLengthNeeded); private const short SQL_HANDLE_ENV = 1; private const short SQL_HANDLE_DBC = 2; private const int SQL_ATTR_ODBC_VERSION = 200; private const int SQL_OV_ODBC3 = 3; private const short SQL_SUCCESS = 0; private const short SQL_NEED_DATA = 99; private const short DEFAULT_RESULT_SIZE = 1024; private const string SQL_DRIVER_STR = "DRIVER=SQL SERVER"; #endregion /// /// 获取网内的数据库服务器名称(API方式) /// /// 服务器名称数组 public static string[] GetServers() { string list = string.Empty; IntPtr henv = IntPtr.Zero; IntPtr hconn = IntPtr.Zero; System.Text.StringBuilder inString = new System.Text.StringBuilder(SQL_DRIVER_STR); System.Text.StringBuilder outString = new System.Text.StringBuilder(DEFAULT_RESULT_SIZE); short inStringLength = (short)inString.Length; short lenNeeded = 0; try { if (SQL_SUCCESS == SQLAllocHandle(SQL_HANDLE_ENV, henv, out henv)) { if (SQL_SUCCESS == SQLSetEnvAttr(henv, SQL_ATTR_ODBC_VERSION, (IntPtr)SQL_OV_ODBC3, 0)) { if (SQL_SUCCESS == SQLAllocHandle(SQL_HANDLE_DBC, henv, out hconn)) { if (SQL_NEED_DATA == SQLBrowseConnect(hconn, inString, inStringLength, outString, DEFAULT_RESULT_SIZE, out lenNeeded)) { if (DEFAULT_RESULT_SIZE lenNeeded) { outString.Capacity = lenNeeded; if (SQL_NEED_DATA != SQLBrowseConnect(hconn, inString, inStringLength, outString, lenNeeded, out lenNeeded)) { throw new ApplicationException("Unabled to aquire SQL Servers from ODBC driver."); } } list = outString.ToString(); int start = list.IndexOf("{") + 1; int len = list.IndexOf("}") - start; if ((start > 0) && (len > 0)) { list = list.Substring(start, len); } else { list = string.Empty; } } } } } } catch { list = string.Empty; } finally { if (hconn != IntPtr.Zero) { SQLFreeHandle(SQL_HANDLE_DBC, hconn); } if (henv != IntPtr.Zero) { SQLFreeHandle(SQL_HANDLE_ENV, hconn); } } string[] array = null; if (list.Length > 0) { array = list.Split(','); } return array; } /// /// 获取网内的数据库服务器名称(qlClientFactory方式) /// /// 服务器名称数组 public static string[] GetServersBySqlClientFactory() { DataTable dataSources = SqlClientFactory.Instance.CreateDataSourceEnumerator().GetDataSources(); DataColumn column2 = dataSources.Columns["ServerName"]; DataColumn column = dataSources.Columns["InstanceName"]; DataRowCollection rows = dataSources.Rows; string[] array = new string[rows.Count]; for (int i = 0; i ) { string str2 = rows[i][column2] as string; string str = rows[i][column] as string; if (((str == null) || (str.Length == 0)) || ("MSSQLSERVER" == str)) { array[i] = str2; } else { array[i] = str2 + @"\" + str; } } Array.Sortstring>(array); return array; } /// /// 根据不带数据库的连接字符串,遍历查找出所有数据库实例 /// /// 指定服务器的所有数据库 public string[] GetDataBases() { Liststring> list = new Liststring>(); SqlConnection sqlConnection = new SqlConnection(ConnectString); string[] result; try { sqlConnection.Open(); SqlCommand sqlCommand = new SqlCommand("select name AS 数据库 from master..sysdatabases", sqlConnection); SqlDataReader sqlDataReader = sqlCommand.ExecuteReader(); while (sqlDataReader.Read()) { list.Add(sqlDataReader.GetString(0)); } sqlDataReader.Close(); string[] array = new string[] { "master", "tempdb", "model", "msdb" }; string[] array2 = array; for (int i = 0; i ) { string item = array2[i]; try { list.Remove(item); } catch { } } result = list.ToArray(); } catch { result = list.ToArray(); } finally { sqlConnection.Close(); } return result; } /// /// 获取SqlServer指定数据库的所有表 /// /// 表集合,出错则产生异常 public string[] GetTables() { string sql = "select object_name (id) from sysobjects where xtype = 'u' and objectproperty (id,'IsMSShipped') = 0"; DataTable dt = ReturnDataTable(sql); Liststring> Ls = new Liststring>(); for (int i = 0; i ) { Ls.Add(dt.Rows[i][0].ToString()); } return Ls.ToArray(); } /// /// 获取指定表的所有列 /// /// 表名 /// 列集合,出错则产生异常 public string[] GetColumns(string TableName) { string sql = string.Format("select name from syscolumns where id=object_id('{0}')",TableName); try { Liststring> Ls = new Liststring>(); DataTable dt = ReturnDataTable(sql); for (int i = 0; i ) { Ls.Add(dt.Rows[i][0].ToString()); } return Ls.ToArray(); } catch { throw; } } } }

InnoDBBufferPool reduces disk I/O by caching data and indexing pages, improving database performance. Its working principle includes: 1. Data reading: Read data from BufferPool; 2. Data writing: After modifying the data, write to BufferPool and refresh it to disk regularly; 3. Cache management: Use the LRU algorithm to manage cache pages; 4. Reading mechanism: Load adjacent data pages in advance. By sizing the BufferPool and using multiple instances, database performance can be optimized.

Compared with other programming languages, MySQL is mainly used to store and manage data, while other languages such as Python, Java, and C are used for logical processing and application development. MySQL is known for its high performance, scalability and cross-platform support, suitable for data management needs, while other languages have advantages in their respective fields such as data analytics, enterprise applications, and system programming.

MySQL is worth learning because it is a powerful open source database management system suitable for data storage, management and analysis. 1) MySQL is a relational database that uses SQL to operate data and is suitable for structured data management. 2) The SQL language is the key to interacting with MySQL and supports CRUD operations. 3) The working principle of MySQL includes client/server architecture, storage engine and query optimizer. 4) Basic usage includes creating databases and tables, and advanced usage involves joining tables using JOIN. 5) Common errors include syntax errors and permission issues, and debugging skills include checking syntax and using EXPLAIN commands. 6) Performance optimization involves the use of indexes, optimization of SQL statements and regular maintenance of databases.

MySQL is suitable for beginners to learn database skills. 1. Install MySQL server and client tools. 2. Understand basic SQL queries, such as SELECT. 3. Master data operations: create tables, insert, update, and delete data. 4. Learn advanced skills: subquery and window functions. 5. Debugging and optimization: Check syntax, use indexes, avoid SELECT*, and use LIMIT.

MySQL efficiently manages structured data through table structure and SQL query, and implements inter-table relationships through foreign keys. 1. Define the data format and type when creating a table. 2. Use foreign keys to establish relationships between tables. 3. Improve performance through indexing and query optimization. 4. Regularly backup and monitor databases to ensure data security and performance optimization.

MySQL is an open source relational database management system that is widely used in Web development. Its key features include: 1. Supports multiple storage engines, such as InnoDB and MyISAM, suitable for different scenarios; 2. Provides master-slave replication functions to facilitate load balancing and data backup; 3. Improve query efficiency through query optimization and index use.

SQL is used to interact with MySQL database to realize data addition, deletion, modification, inspection and database design. 1) SQL performs data operations through SELECT, INSERT, UPDATE, DELETE statements; 2) Use CREATE, ALTER, DROP statements for database design and management; 3) Complex queries and data analysis are implemented through SQL to improve business decision-making efficiency.

The basic operations of MySQL include creating databases, tables, and using SQL to perform CRUD operations on data. 1. Create a database: CREATEDATABASEmy_first_db; 2. Create a table: CREATETABLEbooks(idINTAUTO_INCREMENTPRIMARYKEY, titleVARCHAR(100)NOTNULL, authorVARCHAR(100)NOTNULL, published_yearINT); 3. Insert data: INSERTINTObooks(title, author, published_year)VA


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