How to retrieve Oracle long type data using the ODP.NET driver in Visual Studio?

To retrieve Oracle LONG type data using the ODP.NET driver in Visual Studio, you can follow these steps:

1. Set InitialLONGFetchSize: You already mentioned setting InitialLONGFetchSize = -1. This is a correct approach as it allows the driver to fetch the entire LONG data when retrieving it.
2. Using the ODP.NET Driver: Ensure that you are using the ODP.NET driver correctly to access the LONG data. If you are using OracleDataReader, you can retrieve LONG data by calling GetOracleString or GetOracleBinary methods, depending on the type of LONG data you are dealing with.
3. Connection Configuration: Since you are using IVsDataConnection, you may need to check if there is a way to configure the connection string or properties to include the InitialLONGFetchSize. This might not be directly exposed through IVsDataConnection, so you may need to look into the underlying connection string or configuration options available in ODP.NET.
4. Testing with a Simple Query: As a test, run a simple query that selects the LONG column directly to see if it returns data. This can help isolate whether the issue lies with the connection setup or the way the data is being fetched.

If you continue to face issues, consider checking the Oracle documentation for any specific configurations or limitations regarding LONG data types and ODP.NET.

References:

• Oracle Data Type Mappings
• Getting Long Data

Thank you for reaching out.

Oracle LONG columns return empty strings because InitialLONGFetchSize defaults to 0, so no LONG data is fetched.

Set InitialLONGFetchSize to -1 in your connection string and use ODP.NET reader methods.

var csb = new OracleConnectionStringBuilder(vsConnStr)

{

    InitialLONGFetchSize = -1

};

var conn = new OracleConnection(csb.ToString());

conn.Open();

var cmd = new OracleCommand("SELECT DATA_DEFAULT FROM ALL_TAB_COLS WHERE TABLE_NAME='YourTable'", conn);

var reader = cmd.ExecuteReader();

var longValue = reader.GetOracleString(0);

This ensures the entire LONG value is retrieved.

Please let us know if you require any further assistance, we’re happy to help.

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