using (SqlConnection conn = new SqlConnection(GetAppValue("msConStr"))) { try { conn.Open(); } catch { // } SqlCommand cmd = new SqlCommand("SELECT f1 FROM a where id = 1", conn); if (cmd.ExecuteScalar() == null) { } } 其他数据库请看 http://hi.baidu.com/dotnet365/blog/item/ff04de73955eeb128601b0e7.html
DataTable dt = new DataTable("tablename"); using (SqlConnection conn = new SqlConnection(GetAppValue("msConStr"))) { try { conn.Open(); } catch { // } SqlCommand cmd = new SqlCommand("SELECT * FROM " + dt.TableName, conn); SqlDataAdapter dap = new SqlDataAdapter(cmd); try { dap.Fill(dt); } catch { // } }
{
try
{
conn.Open();
}
catch
{
//
} SqlCommand cmd = new SqlCommand("SELECT f1 FROM a where id = 1", conn); if (cmd.ExecuteScalar() == null)
{ }
}
其他数据库请看
http://hi.baidu.com/dotnet365/blog/item/ff04de73955eeb128601b0e7.html
using (SqlConnection conn = new SqlConnection(GetAppValue("msConStr")))
{
try
{
conn.Open();
}
catch
{
//
} SqlCommand cmd = new SqlCommand("SELECT * FROM " + dt.TableName, conn); SqlDataAdapter dap = new SqlDataAdapter(cmd); try
{
dap.Fill(dt);
}
catch
{
//
}
}
public string Source = "Server=(local);integrated security=SSPI;DataBase=数据库名称";
SqlConnection conn = new SqlConnection(Source);
conn.Open();
连接完成
2)数据库增删改查;//str 用来实现对数据库的增删改查自己写
string str="select * from table...";
SqlCommand cmd = new SqlCommand(str, conn);
//结果操作不返回结果
cmd.ExecuteNonQuery();
//返回查询行的结果
cmd.ExecuteScalar();