candlecao
commented
3 months ago Here is another answer from Customer Support Assistant from https://virtuoso.openlinksw.com/:
1. Prepare the CSV File:
Ensure your CSV file is properly formatted and accessible from the Virtuoso server.
2. Create a Procedure to Read CSV:
Write a Virtuoso PL procedure that uses the DB.DBA.CSVREAD function to read the CSV file.
3. Convert CSV Data to RDF:
Within the procedure, convert the CSV data to RDF triples and insert them into the Virtuoso RDF store.
Here is an example of how you can achieve this:
-- Create a procedure to read CSV and convert to RDF
CREATE PROCEDURE CSV_to_RDF (IN csv_file VARCHAR)
{
DECLARE c INT;
DECLARE row VARCHAR;
DECLARE col1 VARCHAR;
DECLARE col2 VARCHAR;
DECLARE col3 VARCHAR;
-- Open the CSV file
c := DB.DBA.CSVREAD (csv_file, ',', '"');
-- Loop through each row in the CSV file
WHILE (row := DB.DBA.CSVNEXT (c)) IS NOT NULL
DO
-- Split the row into columns
col1 := DB.DBA.CSVGET (c, 1);
col2 := DB.DBA.CSVGET (c, 2);
col3 := DB.DBA.CSVGET (c, 3);
-- Insert RDF triples into the RDF store
DB.DBA.RDF_INSERT_TRIPLE (
iri_to_id ('http://example.org/resource/' || col1),
iri_to_id ('http://example.org/property/hasValue'),
iri_to_id ('http://example.org/resource/' || col2)
);
DB.DBA.RDF_INSERT_TRIPLE (
iri_to_id ('http://example.org/resource/' || col1),
iri_to_id ('http://example.org/property/hasDescription'),
col3
);
END;
-- Close the CSV file
DB.DBA.CSVCLOSE (c);
};
-- Call the procedure with the path to your CSV file
CALL CSV_to_RDF ('/path/to/your/file.csv');Explanation:
1. Procedure Definition:
The procedure CSV_to_RDF takes the path to the CSV file as an input parameter.
2. Open CSV File:
DB.DBA.CSVREAD function is used to open the CSV file.
3. Read and Process Rows:
A loop reads each row using DB.DBA.CSVNEXT.
Each row is split into columns using DB.DBA.CSVGET.
4. Insert RDF Triples:
RDF triples are inserted into the RDF store using DB.DBA.RDF_INSERT_TRIPLE.
5. Close CSV File:
The CSV file is closed using DB.DBA.CSVCLOSE.
- Note:
Adjust the column indices and RDF properties according to your CSV structure and RDF schema.
Ensure the CSV file path is correct and accessible from the Virtuoso server.
If you need further assistance or a more specific guide, please provide additional details about your CSV structure and the desired RDF schema.
HughWilliams
kidehen
I asked this question to ChatGPT 4o. It answered:
Step 1
Step 2
Next, you needs to create a PL procedure that reads the data from the table and converts it into RDF triples. Here’s an example of a PL procedure:
Step 3
Finally, execute the PL procedure to convert the CSV data to RDF:
My questions are:
When I was executing the
DB.DBA.CSVREAD()function, it promptedUndefined procedure DB.DBA.CSVREAD. I don't know how to activate theCSVREAD()function despite some trials. Then I justINSERTdata using SQL as a substitute method.When I executed the scripts of Step 2 in ISQL, it prompted:
Anyway, could somebody help me out?