Make primary key requirements less restrictive in HANA #41136
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Co-authored-by: Matthias Kuhn <matthias@opengis.ch>
| @@ -71,6 +71,7 @@ class QgsHanaConnection : public QObject | |||
| QString getColumnDataType( const QString &schemaName, const QString &tableName, const QString &columnName ); | |||
| int getColumnSrid( const QString &schemaName, const QString &tableName, const QString &columnName ); | |||
| QgsHanaResultSetRef getColumns( const QString &schemaName, const QString &tableName, const QString &fieldName ); | |||
| bool isTable( const QString &schemaName, const QString &tableName ); | |||
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| bool isTable( const QString &schemaName, const QString &tableName ); | |
| bool isTable( const QString &schemaName, const QString &tableName ) const; |
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Currently, we cannot change this to const because this method calls (indirectly via another non-const method) odbc::Connection::createStatment(), which is not const.
Actually, the question how const-correctness should look like in a database connector is quite interesting. Intuitively, one might expect that methods that don't change database objects are const. However, from a C++-language point of view, const-correctness relates to the state of C++objects.
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I think we should look at it from a pure c++ perspective. And use mutable to hide away implementation details.
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I had a closer look at the QgsHanaConnection class. Currently, no method is const. For consistency, I'd keep the new method as not const as well.
It's not quite clear to me, which methods should be const in this class. Most of them require the creation of a statement, which is a modification of the mConnection member.
Is it okay to keep it non-const for the time being and to come up with a criteria for making methods const in this class @m-kuhn? We could then do the constness changes in a separate follow-up pull request.
This change allows creating a valid HANA provider with undefined primary key.