@Override
	RecordIterator getExternalSymbolsByMemoryAddress(Address extProgAddr) throws IOException {
		StringField addrField = new StringField(extProgAddr.toString());
		return symbolTable.indexIterator(SYMBOL_EXTERNAL_PROG_ADDR_COL, addrField, addrField, 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