Purpose
Opens a LOB for reading.
Syntax
tdr.LobOpen_CL(locator, start, maxlength)
- locator
- Parameter type: integer
The locator of the LOB stored in the table.
- start
- Parameter type: numeric
Start reading at this position in the LOB.
- maxlength
- Parameter type: numeric
The maximum number of bytes to read.
Return Value
A list with two elements: contextID and LOBlen. This list can be used to read the LOB.
Usage Notes
This function is valid only if called from the table operator.
An error is raised if the function is called from the contract function.
Example: Open a LOB for Reading
Consider an input table with 5 attributes: (int, int, int, int, clob). This example shows how to read the last attribute of the current row as follows:
- Get the LOB locator
- Open the LOB
- Read the LOB
- Close the LOB
# Open the input stream
inHandle <- tdr.Open("R", 0, 0);
# Get the 5th attribute in the current row (LOB locator)
att5 <- tdr.GetAttributeByNdx(inHandle, 4, NULL);
# Open the LOB for reading
inlob <- tdr.LobOpen_CL(att5,0,0);
# Read the LOB, convert it to character, and print it
string <- tdr.LobRead(inlob$contextID, inlob$LOBlen);
print(rawToChar(string$buffer));
# Close the LOB
tdr.LobClose(inlob$contextID);