public static DatabaseOp extend(
DatabaseOp wrapped, Map<ColumnName, Expression> extensions, Vendor vendor) {
if (extensions.isEmpty()) return wrapped;
List<ProjectionSpec> specs = ProjectionSpec.createFromColumns(wrapped.getColumns());
for (ColumnName column : extensions.keySet()) {
specs.add(ProjectionSpec.create(column, extensions.get(column), vendor));
}
return ProjectOp.create(wrapped, specs);
}
