Decrement.md

Decrement through the open index

Decrement command is modifying database and can only be done through writing socket.

Open an index with columns 'key', 'num'. And reduces the value of the column key by 0, the column num by 3, where key = 106.

$writer = new \HS\Writer('localhost', 9999);

$indexId = $writer->getIndexId(
    $this->getDatabase(),
    $this->getTableName(),
    'PRIMARY',
    array('key', 'num')
);
$decrementQuery = $writer->decrementByIndex($indexId, '=', array(106), array(0, 3));

If you are fully confident in your query, you can simply send it to server, thus save time and memory:

$writer->sendQueries();

If you want to check that the command completed successfully:

$writer->getResultList();
if($decrementQuery->getResult()->isSuccessfully()){
    // query successfully processed
}

Another way to execute the query:

$decrementQuery->execute(); // query was sent and the results on this query and all from the queue were parsed
$decrementResult = $decrementQuery->getResult();

Decrement with the opening index

This command will check whether there's a required index if it isn't, first open and then perform Decrement.

$incrementQuery = $writer->decrement(
    array('key', 'num'),
    $this->getDatabase(),
    $this->getTableName(),
    'PRIMARY',
    '=',
    array(106),
    array(0, 5)
);

$writer->getResultList();

Decrement using QueryBuilder

When initializing specify which columns and how much will be raised.

If you specify a value with out number,it'll be decreased by 1.

'Where' conditions indicate through screening.

$decrementQueryBuilder = QueryBuilder::decrement(array('key' => 0, 'num'))
->fromDataBase($this->getDatabase())
->fromTable($this->getTableName())
->where(Comparison::EQUAL, array('key' => 104));

$decrementQuery = $writer->addQueryBuilder($decrementQueryBuilder);
$writer->getResultList();