public void getAlterTableStmtDefaultConstraint(DefaultConstraint dc, Table tb, List<String> constraints) {
    if (!DefaultConstraint.isNotEmpty(dc)) {
      return;
    }
    Map<String, String> colType = getTableColumnsToType(tb);
    Map<String, List<DefaultConstraintCol>> defaultConstraints = dc.getDefaultConstraints();
    for (String constraintName : defaultConstraints.keySet()) {
      List<DefaultConstraintCol> defaultConstraintCols = defaultConstraints.get(constraintName);
      for (DefaultConstraintCol col : defaultConstraintCols) {
        ST command = new ST(ALTER_TABLE_ADD_DEFAULT_CONSTRAINT);
        command.add(DATABASE_NAME, unparseIdentifier(dc.getTableName()));
        command.add(TABLE_NAME, unparseIdentifier(dc.getTableName()));
        command.add(COLUMN_NAME, unparseIdentifier(col.colName));
        command.add(COL_TYPE, colType.get(col.colName));
        command.add(DEFAULT_VALUE, col.defaultVal);
        command.add(ENABLE, col.enable);
        command.add(VALIDATE, col.validate);
        command.add(RELY, col.rely);
        constraints.add(command.render());
      }
    }
  }
Parses the basic table statistics for the given table.

@param tbl
@return Returns the alter table .... update statistics for table
ql/src/java/org/apache/hadoop/hive/ql/exec/DDLPlanUtils.java