public SQLNotNullConstraintBuilder setColName(String colName) {
    assert columns.isEmpty();
    columns.add(colName);
    return this;
  }
Builder for {@link SQLNotNullConstraint}.  Only requires what {@link ConstraintBuilder} requires.
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/client/builder/SQLNotNullConstraintBuilder.java