Purpose
Reads a LOB.
Syntax
tdr.LobRead(contextID, length)
- contextID
- Parameter type: integer
The context ID returned by the tdr.LobOpen_CL function.
- length
- Parameter type: numeric
The number of bytes to read.
Return Value
A raw vector with the LOB content.
If the function encounters an error, NULL is returned.
Usage Notes
Before you call this function, you must call the tdr.LobOpen_CL function to get the context ID. Then pass this context ID as an argument to this function.
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: Read a LOB
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);