static String extractSqlString(Object value) {
    if (value == null) return null;
    return value.toString();
  }
Convert a boolean value returned from the RDBMS to a Java Boolean object.
MySQL has booleans, but e.g. Derby uses 'Y'/'N' mapping and Oracle DB
doesn't supports boolean, so we have used Number to store the value,
which maps to BigDecimal.

@param value
         column value from the database
@return The Boolean value of the database column value, null if the column
        value is null
@throws MetaException
          if the column value cannot be converted into a Boolean object
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/MetastoreDirectSqlUtils.java