ODBC without data on "data" table
Hi everyone,
I'm trying to query from an ODBC client and I can only see data from the "aggregates" and "views" tables.
When I try with the "data" table, the results are always empty.
I thought it was a permissions problem in the Views tile on Canary. I saw that ANONYMOUS LOGON is allowed in the Access menu. I tried to remove and add it again, but it didn't work.
I also tried with a user and password in the ODBC client, but that didn't work either.
Then I tried enabling "Security" and added the user and ANONYMOUS LOGON to the root of the views, but still nothing.
What could I be missing?
Thank you!
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Hi rodrigopoyanco
I would disable Views Security and ensure the Anonymous Logon is listed on the Views access list just so we can eliminate any permissions issues. The ODBC client makes an anonymous connection by default. What query are you trying to make against the "data" table? I'm wondering if there is no data for the tag(s) in the time range you are requesting. If you don't specify a start or end time, we place some limits as to what we will return just so it doesn't overwhelm the system. See https://helpcenter.canarylabs.com/t/h7hvlm9/schema-version-23#data for those details.
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Hi Steve Mason
Thank you for your reply.
I finally managed to resolve the security issue. Thank you for your tips.
Also, I had a misconception about the '%' character. I was trying to use it at the beginning and the end of the string in the "LIKE" clause, but I realized that it only works at the end of the string.
Thank you. Everything is working fine now.
Regards,
RP
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Steve Mason said:
we place some limits as to what we will return just so it doesn't overwhelm the systemSteve Mason How much is the limit for an ODBC query? It is a configuration parameter?
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rodrigopoyanco Glad you were able to resolve it! We do place some default limits on a query if you don't pass in start and end times. This is just a way of preventing the user from accidentally requesting EVERYTHING from the Historian. For example, if you're requesting raw data, we will only give you the last hour's data for each tag unless, you specify a start and end time. You can see the other limits we default to if you look at the article I posted. I was just trying to determine if you were passing in a time range as that could've been a reason why nothing was showing up. There may not have been any recent raw data within the default time range.
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