`DatabaseMetaData.getFunctions(…)` should accept a null schema

[desruisseaux]

The JDBC Javadoc of DatabaseMetaData.getFunctions(…) said:

schemaPattern - a schema name pattern; must match the schema name as it is stored in the database; "" retrieves those without a schema; null means that the schema name should not be used to narrow the search

Therefore, setting the schemaPattern argument to null in the following code snippet should return all functions. However, that code prints nothing with DuckDB 1.2.1:

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;

public class TestDuckDB {
    public static void main(String[] args) throws Exception {
        try (Connection c = DriverManager.getConnection("jdbc:duckdb:/...something.db")) {
            try (ResultSet r = c.getMetaData().getFunctions(null, null, "%")) {
                while (r.next()) {
                    System.out.println(r.getString("FUNCTION_NAME"));
                }
            }
        }
    }
}

If we replace the schemaPattern argument (the last null) by "%" in the call to getFunctions(…), it works. The fix for this issue may be simply to replace null by "%" internally in the JDBC driver.

[desruisseaux]

It also seems that toFunctionNames(…) does not recognize the escape character declared in getSearchStringEscape(), which is \. When the spatial extension is installed (LOAD spatial) , the following gives me the list of spatial functions as expected:

c.getMetaData().getFunctions(null, "%", "ST_%")

But if I replace "ST_%" by "ST\\_%" in order to require specifically the underscore character instead of any character, then I get an empty ResultSet.

[staticlibs]

@desruisseaux

Just FYI, both problems should be fixed by #167. Additionally null value for functionNamePattern is now supported as a wildcard to be consistent with tableNamePattern handling in other introspection functions.

[desruisseaux]

Thanks!