Oracle数据库中LONG类型字段的存取

Oracle中存取4000字节以上大文本类型可以用此数据类型，其在C#中的读写方法如下：

注意需要引用：System.Data.OracleClient

然后添加命名空间：using System.Data.OracleClient


Oracle建库脚本：




CREATE TABLE TEST
(
AGREEMENT_ID CHAR(3) NOT NULL,
AGREEMENT_CONTENT LONGNULL
   )

插入数据：


protected void Button1_Click(object sender, EventArgs e)
{
OracleConnection conn = new OracleConnection
(@\"assword=XXXXXX;User ID=hk;
Data Source=wealthersist Security Info=True\");
conn.Open();
OracleCommand cmd = new OracleCommand(\"Select * From TEST\", conn);
string sql = \"Insert Into TEST (AGREEMENT_ID, AGREEMENT_CONTENT)  
Values(_ID,  _Value)\";
cmd.CommandText = sql;
cmd.Parameters.Add(\"_ID\", this.TextBox2.Text);
cmd.Parameters.Add(\"_Value\", this.TextBox1.Text);
cmd.ExecuteNonQuery();
conn.Close();
   }

读取数据：


protected void Button2_Click(object sender, EventArgs e)
{
OracleConnection conn = new OracleConnection
(@\"assword=XXXXXX;User ID=hk;Data Source=wealth;
Persist Security Info=True\");
conn.Open();
string sql = \"Select  *  From  TEST where AGREEMENT_ID = _ID\";
OracleDataAdapter da = new OracleDataAdapter(sql, conn);
da.SelectCommand.Parameters.Add(\"_ID\", this.TextBox2.Text);
DataSet ds = new DataSet();
da.Fill(ds);
this.TextBox1.Text = ds.Tables[0].Rows.Count.ToString();
this.TextBox1.Text = ds.Tables[0].Rows[0][\"AGREEMENT_CONTENT\"].ToString();
conn.Close();
   }