oracle 如何将 CLOB 字段读入 C# 变量？
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How to read a CLOB field into a C# variable?
提问by user1298925
Possible Duplicate:
Why Do I get OutOfRange Exception in GetOrdinal Function of this CLOB field?
I need to read a CLOB field from an ORACLE table int a C# variable of type String. Does anyone know how to accomplish this task?
This is what I have done but I am getting an IndexOutofRange when calculating the GetOrdinal of the field. Thanks in advance.
这就是我所做的，但是在计算该字段的 GetOrdinal 时我得到了一个 IndexOutofRange。提前致谢。
public void ReadFunction(string FName, out string fContent)
{
OracleCommand command = _connection.CreateCommand();
OracleTransaction transaction = _connection.BeginTransaction();
command.Transaction = transaction;
command.CommandText = "SELECT TO_CLOB(TO_NCLOB(FUNCTION_SCRIPT)) FROM IS_FUNCTION where FNAME=:fName ";
command.Parameters.Add("FName", OracleType.NVarChar).Value = FName;
OracleDataReader odr = command.ExecuteReader();
int temp = odr.GetOrdinal("FUNCTION_SCRIPT");
OracleLob myLob = odr.GetOracleLob(temp);
fContent = (String)myLob.Value;
odr.close();
}
回答by NicoRiff
This is the code to get the Blob, then you should cast it as astring in the way you need it. I do not know the format you need.
这是获取 Blob 的代码，然后您应该按照您需要的方式将其转换为字符串。我不知道你需要的格式。
// create and open connection
// change for your environment
string connStr = "User Id=pm; Password=pm; Data Source=orcllx; Pooling=false";
OracleConnection con = new OracleConnection(connStr);
try
{
con.Open();
}
catch (OracleException ex)
{
MessageBox.Show(ex.Message);
}
// statement to get a blob
string sql = "select ad_composite from print_media where product_id=3106 and
ad_id=13001";
// create command object
// InitialLOBFetchSize
// defaults to 0
OracleCommand cmd = new OracleCommand(sql, con);
cmd.InitialLOBFetchSize = 8192;
// create a datareader
OracleDataReader dr = cmd.ExecuteReader();
// read the single row result
try
{
dr.Read();
}
catch (OracleException ex)
{
MessageBox.Show(ex.Message);
}
// use typed accessor to retrieve the blob
OracleBlob blob = dr.GetOracleBlob(0);
// create a memory stream from the blob
MemoryStream ms = new MemoryStream(blob.Value);
// set the image property equal to a bitmap
// created from the memory stream
pictureBox1.Image = new Bitmap(ms);
