@Override
	RecordIterator getExternalSymbolsByOriginalImportName(String extLabel) throws IOException {
		StringField extLabelField = new StringField(extLabel);
		return symbolTable.indexIterator(SYMBOL_ORIGINAL_IMPORTED_NAME_COL, extLabelField,
			extLabelField, true);
	}
SymbolDatabaseAdapter for version 3

This version added additional sparse columns to store optional data specific to certain
symbol types.  The adhoc string data column was eliminated.
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/symbol/SymbolDatabaseAdapterV4.java