作者：raymondxiao518 | 来源：互联网 | 2021-12-12 12:51
1、常用的T-Sql语句
查询：SELECT * FROM tb_test WHERE ID='1' AND name='xia'
SELECT * FROM tb_test
插入：INSERT INTO tb_test VALUES('xia','123')
INSERT INTO tb_test(name) VALUES('xia')
更新：UPDATE tb_test SET password='234' WHERE ID='1'
删除：DELETE FROM tb_test WHERE ID='1'
DELETE tb_test WHERE ID='1'
2、在vs2010中获取数据库连接字符串
string cOnnectionString= Properties.Settings.Default.DatabaseTestConnectionString;
3、SqlCommand类型
查询：
代码如下:
using (SqlConnection cOnnection= new SqlConnection(connectionString))
{
try
{
SqlCommand command = new SqlCommand(selectStr, connection);
command.Connection.Open();
SqlDataReader reader = command.ExecuteReader();
while (reader.Read())
label1.Text = "name：" + reader["name"].ToString(); //数据读取
command.Connection.Close();
}
catch (SqlException ex)
{
throw ex;
}
}
插入、修改、删除：
代码如下:
using (SqlConnection cOnnection= new SqlConnection(connectionString))
{
try
{
SqlCommand command = new SqlCommand(cmdStr, connection);
command.Connection.Open();
command.ExecuteNonQuery();
command.Connection.Close();
}
catch (SqlException ex)
{
throw ex;
}
}
4、DataTable类型，查询、添加、修改、删除
DataTable使用查询、添加、删除、修改时，需要用到SqlDataAdapter类
string selectStr = "SELECT * FROM tb_test2";
查询：
代码如下:
using (SqlConnection cOnnection= new SqlConnection(connectionString))
{
try
{
SqlDataAdapter adapter = new SqlDataAdapter(selectStr, connection);
DataTable dataTable = new DataTable();
adapter.Fill(dataTable);
//数据读取
label1.Text = dataTable.Rows[0][0].ToString();
}
catch (SqlException ex)
{
throw ex;
}
}
添加：
代码如下:
using (SqlConnection cOnnection= new SqlConnection(connectionString))
{
try
{
SqlDataAdapter adapter = new SqlDataAdapter(selectStr, connection);
DataTable dataTable = new DataTable();
adapter.Fill(dataTable);
//添加数据
DataRow newRow = dataTable.NewRow();
newRow["id"] = "tesr";
newRow["name"] = "111";
dataTable.Rows.Add(newRow);
SqlCommandBuilder builder = new SqlCommandBuilder(adapter);
adapter.Update(dataTable); //更新到数据库
}
catch (SqlException ex)
{
throw ex;
}
}
修改：
代码如下:
using (SqlConnection cOnnection= new SqlConnection(connectionString))
{
try
{
SqlDataAdapter adapter = new SqlDataAdapter(selectStr, connection);
DataTable dataTable = new DataTable();
adapter.Fill(dataTable);
//修改数据
DataRow updateRow = dataTable.Rows[0];
updateRow["id"] = "update";
updateRow["name"] = "222";
SqlCommandBuilder builder = new SqlCommandBuilder(adapter);
adapter.Update(dataTable); //更新到数据库
}
catch (SqlException ex)
{
throw ex;
}
}
删除：
代码如下:
using (SqlConnection cOnnection= new SqlConnection(connectionString))
{
try
{
SqlDataAdapter adapter = new SqlDataAdapter(selectStr, connection);
DataTable dataTable = new DataTable();
adapter.Fill(dataTable);
dataTable.Rows[0].Delete(); //删除记录
SqlCommandBuilder builder = new SqlCommandBuilder(adapter);
adapter.Update(dataTable); //更新到数据库
}
catch (SqlException ex)
{
throw ex;
}
}
5、DataSet类型
DataSet操作跟DataTabel操作基本是一样的，只是DataSet可以储存有多个表格，所以就多做介绍了
6、个人总结
个人感觉，用 SqlCommand比较灵活，而DataSet是实现ADO.NET断开式连接的核心，比较安全
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