When is the getSchema function called? - google-data-studio

Does anyone know when the getSchema function is called, or what calls it?
For that matter does anyone know of any documentation that outlines the flow between the Google Data Studio Connector functions.

So I think I can answer my own question, but if anyone can add any clarification that would still be welcome.
It appears that this function provides the full list of connector fields, specifically when the connector is connected to a data source.
It may be called at other points as well which where some further clarification would be useful.

getSchema() is called by Data Studio when Data Studio needs to know the schema. This usually happens 1) right after you complete the configuration for a community connector or 2) when you are editing a data source in Data Studio and reconnect to it.

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What does the function fn:data() do in exist-db?

I would like to know what the fn:data() function does in exist-db. I can't find the answer anywhere on the web.
It seems you have found one documentation of the data function, however, that is part of the MS SQL Server XQuery support.
In general, the W3C XQuery/XPath/XSLT functions are specified in https://www.w3.org/TR/xpath-functions/, so the data function in https://www.w3.org/TR/xpath-functions/#func-data.
Or use the eXist-db documentation if you want an eXist-db specific documentation, searchable at http://www.exist-db.org/exist/apps/fundocs/index.html: for the data function http://www.exist-db.org/exist/apps/fundocs/view.html?uri=http://www.w3.org/2005/xpath-functions&location=java:org.exist.xquery.functions.fn.FnModule&details=true#data.1
For the data function it might not matter but in general the "XQuery" support in non-XML databases like MS SQL is often not complete and/or not based on the current/latest spec so I would start with the W3C specification and then look at vendor specific documentation for the XQuery implementation in use instead of using third party documentation.
I just found the answer to my own question. If anyone else is wondering about this, you can find more here: https://learn.microsoft.com/en-us/sql/xquery/data-accessor-functions-data-xquery?view=sql-server-ver15

How to get notifications on database column changes

i am using mysql-client library for mysql on node.js server.
I am looking for library in node.js sever that run continously and watch on mysql table column and send notifications when changes occour in table column;
Can anyone please name some libray that i am looking for.
Thanks in advance
use the sql Service Broker.
basically you subscribe to a query, so when your table is updated the server sends a notification of a change to you.
Read this great article
edit: Nevermind, didn't read the question thoroughly enough. sorry! - leaving my answer to anyone else that reads it wrong and thinks its c# :)

Work with Database using Spock and Geb.

I hope someone have already faced an issue to verify that application shows correct data from database. I reviewd how groovy used SQL, but I have no idea where and how I should do that. I'm just starting to use gradle+Spock+Geb for testing application. I have a few files where I described a couple of pages from application, a couple of modules and a file with spock specification. Where and how I need to connect to Oracle DB, use SQL and compare result's data with application's ones?
P.S. I write everything in notepad++ and launch from command line writing 'gradlew firefoxTest'. Does exist any more comfortable way to work with gradle+spock+geb?
Thanks in advance.
Because there are no other answers, I wanted to provide a solution someone at my company thought of. This assumes you already have a project that uses some sort of JDBC. In our case it is JDBI.
The idea is to extend Classloader and then use that to directly access the data access object class via the JVM. That idea should work.
I have not tested it out because it doesn't completely fit our use-case. I'll admit that this does not completely apply to your use case, but technically you could just run the jar of an existing project, which can access the database.

Qt Database issue with scope_identity()

I am trying to debug the scope_Identity() call in qt. To elaborate on that scope_identity supposed to return the sessions last inserted data ID, but this call does not work accordingly in Qt database calls. I am trying to figure if this returns a value from the database driver to Qt codes at all and at this point I manage to track the code executions to
bool QODBCResult::reset (const QString& query)
method in qsql_odbc.cpp class.
In this method it accesses some win32 __stdcall calls, one of which I believe is responsible in connecting and retrieving data from the database.
SQLSetStmtAttr
SQLAllocHandle
SQLExecDirect
I am unable to find the code for these and I appreciate if someone can guide me on this.
Thank you very much in advance.
Did you try to ask your favorite search engine? Perhaps it would guide you to the MSDN documentation pages (e.g. for SQLExecDirect) or to this question on stackoverflow: scope_identity vs ident_current that may contain an answer to your troubles.

What is database /DBMS "patch access"?

Could not find this term very easily on google.
I assume it's the ability to patch a DBMS with an update without stopping service.
Is this correct? If not, please guide me.
Thanks in advance.
jbu
Patch Access usually refers to a service to (preferrable easily) get access to relevant patches (for your dbms in this case).
For more information see:
http://www.databasejournal.com/features/oracle/article.php/3569941/Database-Security-and-Patches--Part-3.htm
http://en.wikipedia.org/wiki/Comparison_of_relational_database_management_systems#Access_Control

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