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

ORALCE建库脚本：

CREATE TABLE TEST
(
    AGREEMENT_ID      CHAR(3) NOT NULL,
    AGREEMENT_CONTENT LONG        NULL
)
插入数据：

    protected void Button1_Click(object sender, EventArgs e)
    {
        OracleConnection conn = new OracleConnection(@"PassWord=XXXXXX;User ID=hk;Data Source=wealth;Persist Security Info=True");
        conn.Open();
        OracleCommand cmd = new OracleCommand("Select * From TEST", conn);
        string sql = "Insert Into TEST (AGREEMENT_ID, AGREEMENT_CONTENT)   Values(:P_ID,   :P_Value)";
        cmd.CommandText = sql;
        cmd.Parameters.Add("P_ID", this.TextBox2.Text);
        cmd.Parameters.Add("P_Value", this.TextBox1.Text);
        cmd.ExecuteNonQuery();
        conn.Close();
    }
读取数据：
    protected void Button2_Click(object sender, EventArgs e)
    {
        OracleConnection conn = new OracleConnection(@"Password=XXXXXX;User ID=hk;Data Source=wealth;Persist Security Info=True");
        conn.Open();
        string sql = "Select   *   From   TEST where AGREEMENT_ID = :P_ID";
        OracleDataAdapter da = new OracleDataAdapter(sql, conn);
        da.SelectCommand.Parameters.Add("P_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();
    }
http://www.cnblogs.com/heekui/archive/2006/12/28/606543.html