写在前面：
在日常的工作中，通常一个项目会大量用的数据库的各种基本操作，因此小编几个常见的数据库的操作封装成了一个dll方便后续的开发使用。SQLserver数据库是最为常见的一种数据库，本文则主要是记录了C#对SQL的连接、增、删、改、查的基本操作，如有什么问题还请各位大佬指教。后续也将对其他几个常用的数据库进行相应的整理。
先声明一个SqlConnection便于后续使用。
private SqlConnection sql_con;//声明一个SqlConnection
sql打开：
/// <summary>
/// SQLserver open
/// </summary>
/// <param name="link">link statement</param>
/// <returns>Success:success; Fail:reason</returns>
public string Sqlserver_Open(string link)
{
try
{
sql_con = new SqlConnection(link); sql_con.Open(); return "success"; } catch (Exception ex) { return ex.Message; } }
sql关闭：
/// <summary>
/// SQLserver close
/// </summary>
/// <returns>Success:success Fail:reason</returns>
public string Sqlserver_Close()
{
try
{
if (sql_con == null)
{
return "No database connection";
}
if (sql_con.State == ConnectionState.Open || sql_con.State == ConnectionState.Connecting)
{
sql_con.Close();
sql_con.Dispose();
}
else
{
if (sql_con.State == ConnectionState.Closed)
{
return "success";
}
if (sql_con.State == ConnectionState.Broken)
{
return "ConnectionState:Broken";
}
}
return "success";
}
catch (Exception ex)
{
return ex.Message;
}
}
sql的增删改：
/// <summary>
/// SQLserver insert,delete,update
/// </summary>
/// <param name="sql">insert,delete,update statement</param>
/// <returns>Success:success + Number of affected rows; Fail:reason</returns>
public string Sqlserver_Insdelupd(string sql)
{
try
{
int num = 0;
if (sql_con == null)
{
return "Please open the database connection first";
}
if (sql_con.State == ConnectionState.Open)
{
SqlCommand sqlCommand = new SqlCommand(sql, sql_con);
num = sqlCommand.ExecuteNonQuery();
}
else
{
if (sql_con.State == ConnectionState.Closed)
{
return "Database connection closed";
}
if (sql_con.State == ConnectionState.Broken)
{
return "Database connection is destroyed";
}
if (sql_con.State == ConnectionState.Connecting)
{
return "The database is in connection";
}
}
return "success" + num;
}
catch (Exception ex)
{
return ex.Message.ToString();
}
}
sql的查：
/// <summary>
/// SQLserver select
/// </summary>
/// <param name="sql">select statement</param>
/// <param name="record">Success:success; Fail:reason</param>
/// <returns>select result</returns>
public DataSet Sqlserver_Select(string sql, out string record)
{
try
{
DataSet dataSet = new DataSet();
if (sql_con == null)
{
record = "Please open the database connection first";
return dataSet;
}
if (sql_con.State == ConnectionState.Open)
{
SqlDataAdapter sqlDataAdapter = new SqlDataAdapter(sql, sql_con);
sqlDataAdapter.Fill(dataSet, "sample");
sqlDataAdapter.Dispose();
record = "success";
return dataSet;
}
if (sql_con.State == ConnectionState.Closed)
{
record = "Database connection closed";
return dataSet;
}
if (sql_con.State == ConnectionState.Broken)
{
record = "Database connection is destroyed";
return dataSet;
}
if (sql_con.State == ConnectionState.Connecting)
{
record = "The database is in connection";
return dataSet;
}
record = "ERROR";
return dataSet;
}
catch (Exception ex)
{
DataSet dataSet = new DataSet();
record = ex.Message.ToString();
return dataSet;
}
}
小编发现以上这种封装方式还是很麻烦，每次对SQL进行增删改查的时候还得先打开数据库，最后还要关闭，实际运用起来比较麻烦。因此对上面两个增删改查的方法进行了重载，在每次进行操作时都先打开数据库，然后关闭数据库。
/// <summary>
/// SQLserver insert,delete,update
/// </summary>
/// <param name="sql">insert,delete,update statement</param>
/// <param name="link">link statement</param>
/// <returns>Success:success + Number of affected rows; Fail:reason</returns>
public string Sqlserver_Insdelupd(string sql, string link)
{
try
{
int num = 0;
using (SqlConnection con = new SqlConnection(link))
{
con.Open();
SqlCommand cmd = new SqlCommand(sql, con);
num = cmd.ExecuteNonQuery();
con.Close();
return "success" + num;
}
}
catch (Exception ex)
{
return ex.Message.ToString();
}
}
/// <summary>
/// SQLserver select
/// </summary>
/// <param name="sql">select statement</param>
/// <param name="link">link statement</param>
/// <param name="record">Success:success; Fail:reason</param>
/// <returns>select result</returns>
public DataSet Sqlserver_Select(string sql, string link, out string record)
{
try
{
DataSet ds = new DataSet();
using (SqlConnection con = new SqlConnection(link))
{
con.Open();
SqlDataAdapter sda = new SqlDataAdapter(sql, con);
sda.Fill(ds, "sample");
con.Close();
sda.Dispose();
record = "success";
return ds;
}
}
catch (Exception ex)
{
DataSet dataSet = new DataSet();
record = ex.Message.ToString();
return dataSet;
}
}
小编只是对简单的知识进行整理，通大家分享并方便自己查看，并无恶意，如有侵权，联系小编，小编将立即删除，谢谢。