code: public String getTableAMultiplicity()
      {
          String ret = "many";
          List<ColumnInfo> tableAPKs = tableA.getPkList();
  
          if (tableAPKs.size() == 0 || tableA.getTableName().equals(tableB.getTableName()))
          {
              return ret;
          }
          if (tableAB == null)
          {
              List<ColumnInfo> fkColumns = this.getColumns();
              Set<ColumnInfo> columnSet = new HashSet<ColumnInfo>();
              columnSet.addAll(fkColumns);
              columnSet.removeAll(tableAPKs);
              if (fkColumns.size() == tableAPKs.size() && columnSet.isEmpty())
              {
                  ret = "one";
                  return ret;
              }
          }
          for (ForeignKey tableBFK : tableB.getForeignKeys().values())
          {
              if (!tableBFK.getTableB().getTableName().equals(tableA.getTableName()))
                  continue;
  
              List<ColumnInfo> tableBRefCols = tableBFK.getRefColumns();
              Set<ColumnInfo> columns = new HashSet<ColumnInfo>();
              columns.addAll(tableBRefCols);
              columns.removeAll(tableAPKs);
              if (columns.isEmpty())
              {
                  ret = "one";
                  break;
              }
          }
          return ret;
      }
docs: Otherwise, it is a 1-1 relationship.