这篇文章给大家分享的是有关C#如何实现结构化查询语言封装的内容。小编觉得挺实用的,因此分享给大家做个参考,一起跟随小编过来看看吧。
SQLHelper.as,代码如下:
使用系统;
使用系统.收藏品;
使用系统.集合。通用;
使用系统.配置;
使用系统.数据;
使用系统.数据。程序
使用系统.查询表达式
使用系统.网
namespaceDBDome
{
///此类为抽象类,
///不允许实例化,在应用时直接调用即可
////摘要
publicsealedclassSqlHelper
{
privateSqlHelper(){}
///摘要
///数据库连接字符串
////摘要
publicationstatreadonlystingconnectionstring=配置管理器.ConnectionStrings['con'].ToString();
//Hashtabletostorecachedparameters
privatedstatashtableparmcache=Hashtable .synchronized(new hashtable());
#region//ExecteNonQuery方法
///摘要
///执行一个不需要返回值的对象命令,通过指定专用的连接字符串。
///使用参数数组形式提供参数列表
////摘要
///paramname='connectionString '一个有效的数据库连接字符串/param
///param name=' cmdType ' sqlcommand命令类型(存储过程,T-SQL语句,等等)/参数
///paramname='cmdText '存储过程的名字或者数据库备份与还原语句/param
///paramname='comm
andParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个数值表示此SqlCommand命令执行后影响的行数</returns>
public static int ExecteNonQuery(string connectionString, CommandType cmdType, string cmdText, SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();
using (SqlConnection conn = new SqlConnection(connectionString))
{
//通过PrePareCommand方法将参数逐个加入到SqlCommand的参数集合中
PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
int val = cmd.ExecuteNonQuery();
//清空SqlCommand中的参数列表
cmd.Parameters.Clear();
return val;
}
}
/// <summary>
///执行一个不需要返回值的SqlCommand命令,通过指定专用的连接字符串。
/// 使用参数数组形式提供参数列表
/// </summary>
/// <param name="cmdType">SqlCommand命令类型 (存储过程, T-SQL语句, 等等。)</param>
/// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个数值表示此SqlCommand命令执行后影响的行数</returns>
public static int ExecteNonQuery(CommandType cmdType, string cmdText, SqlParameter[] commandParameters)
{
return ExecteNonQuery(connectionString, cmdType, cmdText, commandParameters);
}
/// <summary>
///存储过程专用
/// </summary>
/// <param name="cmdText">存储过程的名字</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个数值表示此SqlCommand命令执行后影响的行数</returns>
public static int ExecteNonQueryProducts(string cmdText, SqlParameter[] commandParameters)
{
return ExecteNonQuery(CommandType.StoredProcedure, cmdText, commandParameters);
}
/// <summary>
///Sql语句专用
/// </summary>
/// <param name="cmdText">T_Sql语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个数值表示此SqlCommand命令执行后影响的行数</returns>
public static int ExecteNonQueryText(string cmdText, SqlParameter[] commandParameters)
{
return ExecteNonQuery(CommandType.Text, cmdText, commandParameters);
}
#endregion
#region//GetTable方法
/// <summary>
/// 执行一条返回结果集的SqlCommand,通过一个已经存在的数据库连接
/// 使用参数数组提供参数
/// </summary>
/// <param name="connecttionString">一个现有的数据库连接</param>
/// <param name="cmdTye">SqlCommand命令类型</param>
/// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个表集合(DataTableCollection)表示查询得到的数据集</returns>
public static DataTableCollection GetTable(string connecttionString, CommandType cmdTye, string cmdText, SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();
DataSet ds = new DataSet();
using (SqlConnection conn = new SqlConnection(connecttionString))
{
PrepareCommand(cmd, conn, null, cmdTye, cmdText, commandParameters);
SqlDataAdapter adapter = new SqlDataAdapter();
adapter.SelectCommand = cmd;
adapter.Fill(ds);
}
DataTableCollection table = ds.Tables;
return table;
}
/// <summary>
/// 执行一条返回结果集的SqlCommand,通过一个已经存在的数据库连接
/// 使用参数数组提供参数
/// </summary>
/// <param name="cmdTye">SqlCommand命令类型</param>
/// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个表集合(DataTableCollection)表示查询得到的数据集</returns>
public static DataTableCollection GetTable(CommandType cmdTye, string cmdText, SqlParameter[] commandParameters)
{
return GetTable(cmdTye, cmdText, commandParameters);
}
/// <summary>
/// 存储过程专用
/// </summary>
/// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个表集合(DataTableCollection)表示查询得到的数据集</returns>
public static DataTableCollection GetTableProducts(string cmdText, SqlParameter[] commandParameters)
{
return GetTable(CommandType.StoredProcedure, cmdText, commandParameters);
}
/// <summary>
/// Sql语句专用
/// </summary>
/// <param name="cmdText"> T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个表集合(DataTableCollection)表示查询得到的数据集</returns>
public static DataTableCollection GetTableText(string cmdText, SqlParameter[] commandParameters)
{
return GetTable(CommandType.Text, cmdText, commandParameters);
}
#endregion
/// <summary>
/// 为执行命令准备参数
/// </summary>
/// <param name="cmd">SqlCommand 命令</param>
/// <param name="conn">已经存在的数据库连接</param>
/// <param name="trans">数据库事物处理</param>
/// <param name="cmdType">SqlCommand命令类型 (存储过程, T-SQL语句, 等等。)</param>
/// <param name="cmdText">Command text,T-SQL语句 例如 Select * from Products</param>
/// <param name="cmdParms">返回带参数的命令</param>
private static void PrepareCommand(SqlCommand cmd, SqlConnection conn, SqlTransaction trans, CommandType cmdType, string cmdText, SqlParameter[] cmdParms)
{
//判断数据库连接状态
if (conn.State != ConnectionState.Open)
conn.Open();
cmd.Connection = conn;
cmd.CommandText = cmdText;
//判断是否需要事物处理
if (trans != null)
cmd.Transaction = trans;
cmd.CommandType = cmdType;
if (cmdParms != null)
{
foreach (SqlParameter parm in cmdParms)
cmd.Parameters.Add(parm);
}
}
/// <summary>
/// Execute a SqlCommand that returns a resultset against the database specified in the connection string
/// using the provided parameters.
/// </summary>
/// <param name="connectionString">一个有效的数据库连接字符串</param>
/// <param name="cmdType">SqlCommand命令类型 (存储过程, T-SQL语句, 等等。)</param>
/// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>A SqlDataReader containing the results</returns>
public static SqlDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();
SqlConnection conn = new SqlConnection(connectionString);
// we use a try/catch here because if the method throws an exception we want to
// close the connection throw code, because no datareader will exist, hence the
// commandBehaviour.CloseConnection will not work
try
{
PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
cmd.Parameters.Clear();
return rdr;
}
catch
{
conn.Close();
throw;
}
}
#region//ExecuteDataSet方法
/// <summary>
/// return a dataset
/// </summary>
/// <param name="connectionString">一个有效的数据库连接字符串</param>
/// <param name="cmdType">SqlCommand命令类型 (存储过程, T-SQL语句, 等等。)</param>
/// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>return a dataset</returns>
public static DataSet ExecuteDataSet(string connectionString, CommandType cmdType, string cmdText, SqlParameter[] commandParameters)
{
SqlConnection conn = new SqlConnection(connectionString);
SqlCommand cmd = new SqlCommand();
try
{
PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
SqlDataAdapter da = new SqlDataAdapter();
DataSet ds = new DataSet();
da.SelectCommand = cmd;
da.Fill(ds);
return ds;
}
catch
{
conn.Close();
throw;
}
}
/// <summary>
/// 返回一个DataSet
/// </summary>
/// <param name="cmdType">SqlCommand命令类型 (存储过程, T-SQL语句, 等等。)</param>
/// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>return a dataset</returns>
public static DataSet ExecuteDataSet(CommandType cmdType, string cmdText, SqlParameter[] commandParameters)
{
return ExecuteDataSet(connectionString, cmdType, cmdText, commandParameters);
}
/// <summary>
/// 返回一个DataSet
/// </summary>
/// <param name="cmdText">存储过程的名字</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>return a dataset</returns>
public static DataSet ExecuteDataSetProducts(string cmdText, SqlParameter[] commandParameters)
{
return ExecuteDataSet(connectionString, CommandType.StoredProcedure, cmdText, commandParameters);
}
/// <summary>
/// 返回一个DataSet
/// </summary>
/// <param name="cmdText">T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>return a dataset</returns>
public static DataSet ExecuteDataSetText(string cmdText, SqlParameter[] commandParameters)
{
return ExecuteDataSet(connectionString, CommandType.Text, cmdText, commandParameters);
}
public static DataView ExecuteDataSet(string connectionString, string sortExpression, string direction, CommandType cmdType, string cmdText, SqlParameter[] commandParameters)
{
SqlConnection conn = new SqlConnection(connectionString);
SqlCommand cmd = new SqlCommand();
try
{
PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
SqlDataAdapter da = new SqlDataAdapter();
DataSet ds = new DataSet();
da.SelectCommand = cmd;
da.Fill(ds);
DataView dv = ds.Tables[0].DefaultView;
dv.Sort = sortExpression + " " + direction;
return dv;
}
catch
{
conn.Close();
throw;
}
}
#endregion
#region // ExecuteScalar方法
/// <summary>
/// 返回第一行的第一列
/// </summary>
/// <param name="cmdType">SqlCommand命令类型 (存储过程, T-SQL语句, 等等。)</param>
/// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个对象</returns>
public static object ExecuteScalar(CommandType cmdType, string cmdText, SqlParameter[] commandParameters)
{
return ExecuteScalar(SqlHelper.connectionString, cmdType, cmdText, commandParameters);
}
/// <summary>
/// 返回第一行的第一列存储过程专用
/// </summary>
/// <param name="cmdText">存储过程的名字</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个对象</returns>
public static object ExecuteScalarProducts(string cmdText, SqlParameter[] commandParameters)
{
return ExecuteScalar(SqlHelper.connectionString, CommandType.StoredProcedure, cmdText, commandParameters);
}
/// <summary>
/// 返回第一行的第一列Sql语句专用
/// </summary>
/// <param name="cmdText">者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个对象</returns>
public static object ExecuteScalarText(string cmdText, SqlParameter[] commandParameters)
{
return ExecuteScalar(SqlHelper.connectionString, CommandType.Text, cmdText, commandParameters);
}
/// <summary>
/// Execute a SqlCommand that returns the first column of the first record against the database specified in the connection string
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connectionString">一个有效的数据库连接字符串</param>
/// <param name="cmdType">SqlCommand命令类型 (存储过程, T-SQL语句, 等等。)</param>
/// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>An object that should be converted to the expected type using Convert.To{Type}</returns>
public static object ExecuteScalar(string connectionString, CommandType cmdType, string cmdText, SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();
using (SqlConnection connection = new SqlConnection(connectionString))
{
PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
object val = cmd.ExecuteScalar();
cmd.Parameters.Clear();
return val;
}
}
/// <summary>
/// Execute a SqlCommand that returns the first column of the first record against an existing database connection
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connectionString">一个有效的数据库连接字符串</param>
/// <param name="cmdType">SqlCommand命令类型 (存储过程, T-SQL语句, 等等。)</param>
/// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>An object that should be converted to the expected type using Convert.To{Type}</returns>
public static object ExecuteScalar(SqlConnection connection, CommandType cmdType, string cmdText, SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
object val = cmd.ExecuteScalar();
cmd.Parameters.Clear();
return val;
}
#endregion
/// <summary>
/// add parameter array to the cache
/// </summary>
/// <param name="cacheKey">Key to the parameter cache</param>
/// <param name="cmdParms">an array of SqlParamters to be cached</param>
public static void CacheParameters(string cacheKey, SqlParameter[] commandParameters)
{
parmCache[cacheKey] = commandParameters;
}
/// <summary>
/// Retrieve cached parameters
/// </summary>
/// <param name="cacheKey">key used to lookup parameters</param>
/// <returns>Cached SqlParamters array</returns>
public static SqlParameter[] GetCachedParameters(string cacheKey)
{
SqlParameter[] cachedParms = (SqlParameter[])parmCache[cacheKey];
if (cachedParms == null)
return null;
SqlParameter[] clonedParms = new SqlParameter[cachedParms.Length];
for (int i = 0, j = cachedParms.Length; i < j; i++)
clonedParms[i] = (SqlParameter)((ICloneable)cachedParms[i]).Clone();
return clonedParms;
}
/// <summary>
/// 检查是否存在
/// </summary>
/// <param name="strSql">Sql语句</param>
/// <returns>bool结果</returns>
public static bool Exists(string strSql)
{
int cmdresult = Convert.ToInt32(ExecuteScalar(connectionString, CommandType.Text, strSql, null));
if (cmdresult == 0)
{
return false;
}
else
{
return true;
}
}
/// <summary>
/// 检查是否存在
/// </summary>
/// <param name="strSql">Sql语句</param>
/// <param name="cmdParms">参数</param>
/// <returns>bool结果</returns>
public static bool Exists(string strSql, SqlParameter[] cmdParms)
{
int cmdresult = Convert.ToInt32(ExecuteScalar(connectionString, CommandType.Text, strSql, cmdParms));
if (cmdresult == 0)
{
return false;
}
else
{
return true;
}
}
}
}
本篇博客只涉及到添加数据 (insert into) 并陆续的更新其他SQL操作, 本人希望封装一个全套基本的SQL操作。在以后如果从事后端可以在此扩展 , 不喜勿喷。
本人希望用SqlParameter的方式来构建T-SQL
一 : 构建基本的T-SQL( 没有SqlParameter参数注入 )
using DBDome.model; using System; using System.Collections.Generic; using System.Linq; using System.Reflection; using System.Text; namespace DBDome.com { /// <summary> /// SQL构建器(还没与赋值) /// </summary> public sealed class SQL_Structure { private SQL_Structure() { } /// <summary> /// 添加一个数据的T-SQL的构成 /// </summary> /// <typeparam name="T"></typeparam> /// <param name="model"></param> /// <returns></returns> public static string ADD_T_SQL<T>( T model ) where T : BaseModel { string base_add = @"insert into [{0}] ({1}) values ({2})";//表名 , 列明 , 对应的值 Type model_type = model.GetType(); string[] arr = model_type.Name.Split(new char[] { '.' }); string table_name = arr[arr.Length - 1];//获得表的名称 PropertyInfo[] p_intos = model_type.GetProperties(); StringBuilder table_field_name = new StringBuilder(); StringBuilder table_field_value = new StringBuilder(); PropertyInfo item = null; for (int i = 0; i < p_intos.Length; i++) { item = p_intos[i]; if (item.Name != "id")//不应添加主键 { table_field_name.Append(item.Name + ","); table_field_value.Append("@" + item.Name + ","); } } return String.Format(base_add, table_name, table_field_name.ToString().Substring(0, table_field_name.ToString().Length-1), table_field_value.ToString().Substring(0,table_field_value.ToString().Length-1)); } } }
二 : 好了我现在构造与SQL表映射的模型类
①,所有model的基类:
using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace DBDome.model { public abstract class BaseModel { protected int _id; /// <summary> /// 主键ID号 /// </summary> public virtual int id { get { return this._id; } set { this._id = value; } } } }
② , 继承model的一个类User也是我的一个SQL表名
using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace DBDome.model { public sealed class User : BaseModel { public string name { get; set; } public short sex{ get; set; } public int lv{ get; set; } public string username{ get; set; } public string userpwd{ get; set; } } }
三 , 我们添加一条数据 , 需要构建参数 SqlParameter[]
using DBDome.model; using System; using System.Collections.Generic; using System.Data.SqlClient; using System.Linq; using System.Reflection; using System.Text; using System.Data; namespace DBDome.com { /// <summary> /// SqlParameter 构建 /// </summary> public sealed class SqlParameter_Structure { private SqlParameter_Structure() { } /// <summary> /// 构建T-SQL参数 ADD /// </summary> /// <typeparam name="T"></typeparam> /// <param name="model"></param> /// <returns></returns> public static SqlParameter[] ADD_T_SQL<T>(T model) where T : BaseModel { Type model_type = model.GetType(); PropertyInfo[] p_intos = model_type.GetProperties(); SqlParameter[] sql_param = new SqlParameter[p_intos.Length - 1];//不需要主键 PropertyInfo item = null; string p_name = ""; SqlParameter cell = null; int j = 0; for (int i = 0; i < p_intos.Length; i++) { item = p_intos[i]; p_name = item.Name; if (p_name == "id") continue; // Console.WriteLine("字段 {0} 的类型为 {1} ", p_name ,item.PropertyType); cell = new SqlParameter(p_name, SqlParameter_Structure.Get_SqlDbType_SqlType(item.PropertyType)); cell.Value = item.GetValue(model, null); sql_param[j] = cell; j++; } return sql_param; } private static SqlDbType Get_SqlDbType_SqlType(Type cshaper) { string[] arr = cshaper.ToString().Split(new char[] { '.' }); string toLow = arr[arr.Length - 1].ToLower(); switch (toLow) { case "string": return SqlDbType.NVarChar; break; case "int16": return SqlDbType.Bit; break; case "int32": return SqlDbType.Int; break; default: throw new Exception(String.Format("T-SQL参数没有配对的类型 {0}" ,cshaper)); break; } } } }
感谢各位的阅读!关于“C#如何实现SQL封装”这篇文章就分享到这里了,希望
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