ennuite opened a new issue, #797:
URL: https://github.com/apache/arrow-java/issues/797
### Describe the bug, including details regarding any error messages,
version, and platform.
**Describe the bug, including details regarding any error messages, version,
and platform.**
In Apache Arrow Flight SQL Prepared Statement execution, result set
generating queries should be executed via `CommandPreparedStatementQuery` and
queries that return only the number of affected rows should be executed via
`CommandPreparedStatementUpdate`
In JDBC, `PreparedStatement.execute()` allows for running generic queries,
including SELECT, DML and DDL. For DML/DDL, this method should return `False`
and provide an update count, for SELECT it should return `True` and result set
should be provided.
The cause of the issue is that the driver always follows the Arrow Flight
SQL communications path for result set generating queries, meaning, the query
is always executed via `CommandPreparedStatementQuery` and never via
`CommandPreparedStatementUpdate` This means that the driver tries to execute
DML/DDL as if they were SELECT statements, which can lead to incorrect return
values of PreparedStatement.execute()
Code snippet to reproduce:
```
// connection is a previously established Connection instance to a Flight
SQL server
String insertPreparedStatementSingleRow = "INSERT INTO my_table (name)
VALUES (?)";
try (PreparedStatement pstmt =
connection.prepareStatement(insertPreparedStatementSingleRow)) {
pstmt.setString(1, "My name");
boolean hasResultSet = pstmt.execute();
if (hasResultSet) {
System.out.println("Unexpected: INSERT returned a ResultSet");
try (ResultSet rs = pstmt.getResultSet()) {
// Handle unexpected ResultSet
System.out.println("Unexpected ResultSet...");
}
} else {
// false = Update count available
int updateCount = pstmt.getUpdateCount();
System.out.println("Update count: " + updateCount + " row(s)
affected");
}
}
}
```
This was tested with a Dremio Arrow Flight SQL server, but looking at the
driver's code seems to be an issue that affects all servers.
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