操作数据库步骤:
建议使用using块
1)连接到数据库,
a)创建连接字符串
b)创建连接对象
c)连接打开
2) 执行增、删、改、查,
a)创建命令文本
b)创建命令对象
c)执行命令返回结果到DataAdapter
3)第 2)中的结果保存到内存中的数据表中,以便后续使用
DataSet对象或者DataTable对象,
可以把DataTable对象填充DataSet对象中
DataTable为null时,必须先填充DataColumns定义数据结构
然后才能填充数据到DataRows
示例:
//C# Access
using (OleDbConnection conn = new OleDbConnection())
{
DataTable dt = new DataTable();
conn.ConnectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=";
conn.Open();
using (OleDbCommand cmd = new OleDbCommand())
{
cmd.Connection = conn;
cmd.CommandText = "SELECT* FROM[Table]";
using (OleDbDataAdapter da = new OleDbDataAdapter(cmd))
{
da.Fill(dt);
}
}
foreach (DataColumn dc in dt.Columns)
{
Console.WriteLine(dc.ToString());
}
}
//C# SQL:
using (SqlConnection sqlConn = new SqlConnection())
{
DataTable dt = new DataTable();
sqlConn.ConnectionString = @"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=;Integrated Security=True;Connect Timeout=30";
sqlConn.Open();
using (SqlCommand cmd = new SqlCommand())
{
cmd.Connection = sqlConn;
cmd.CommandText = "SELECT* FROM[Table]";
using (SqlDataAdapter da = new SqlDataAdapter(cmd))
{
da.Fill(dt);
}
foreach (DataColumn dc in dt.Columns)
{
Console.WriteLine(dc.ToString());
}
}
}
请各位指正。
原文:http://www.cnblogs.com/MartianLan/p/5022422.html