public FieldDefinition convertToFieldDefinition(DBAccessor.DBColumnInfo columnInfo) {
    int length = columnInfo.getLength() != null ? columnInfo.getLength() : 0;
    FieldDefinition fieldDefinition = new FieldDefinition(columnInfo.getName(), columnInfo.getType(), length);
    fieldDefinition.setShouldAllowNull(columnInfo.isNullable());

    if (null != columnInfo.getDefaultValue() && isConstraintSupportedAfterNullability()) {
      fieldDefinition.setConstraint("DEFAULT " + escapeParameter(columnInfo.getDefaultValue()));
    }

    return fieldDefinition;
  }
Write create table statement to writer
TODO default Value of column not supported
ambari-server/src/main/java/org/apache/ambari/server/orm/helpers/dbms/GenericDbmsHelper.java