I have got this mongoDB query:
db.b_activity.find(
{token_id:"71e32267108b163ccdd3f59ba06c66674b295499"},
{activity_log:{$slice: -1}}
).pretty();
It gets all the desired results in the mongoDB terminal, but when I write the same query in PHP, it fetches the complete array every time.
MY PHP query:
$get_current_activity = $this->mongo_b_employee->b_activity->findOne(
array('token_id'=>$token_id),
array("activity_log" => array('$slice' => -1))
);
Any suggestions where I am doing something wrong?
PS: I am just trying to access the last array element.
The signature for MongoDB\Collection::findOne() is slightly different from the "shell". It requires the "projection" key in the $options as the second argument:
$get_current_activity=$this->mongo_b_employee->b_activity->findOne(
array('token_id'=>$token_id),
array(
"projection" => array( "activity_log" => array('$slice' => -1) )
)
)
Related
I have created query with date comparison in mongoDB which is working fine
but when I convert that query in PHP array and execute in aggregate method, It does not respond with any of data.
Following is mongoDB Query converted in PHP
$dateStart = new MongoDate(strtotime("2016-06-08T18:30:00.000+0000"));
$pipeline = array(
array('$match' => array(
'EventTS' => array(
'$gte' => $dateStart
)
))
);
When I pass $pipeline in aggregate
$t = $collection->aggregate($pipeline);
Sometime it respond empty records and sometime it respond with following error message
Array
(
[ok] => 0
[errmsg] => aggregation result exceeds maximum document size (16MB)
[code] => 16389
)
It seems my query is right but I am unable to identify what is the exact issue
According to above mentioned description,you just need to fetch all documents having date time greater than specific date time .
It can be accomplished easily utilizing find operation of MongoDB.
Aggregation is useful in cases where we need to perform some calculations on group of data.
Please try executing following code snippet
$date = new MongoDate(strtotime("2016-06-08T18:30:00.000+0000"));
$filter=array('EventTS'=>array('$gte'=>$date));
$data=$collection->find($filter);
Your Query is perfect but as per mongodb define your document size more than 16 MB means your single row which is greater than 16 MB.
For resolve this issue you need to use $project in aggregation that migh be solve these issue.
Eg.
$pipeline = array(
array('$match' => array(
'EventTS' => array(
'$gte' => $dateStart
)
)),
array('$project' => array('<field>'=>' <1 or true>'))
);
OR you can use FINDALL
find(array('EventTS' => array( '$gte' => $dateStart )))
we're often dealing with a code that looks like the following:
return $this->find(
'all', [
'fields' => ['DISTINCT Tag.tag', 'COUNT(Tag.tag) as count'],
'group' => ['Tag.tag'],
'order' => ['count' => 'DESC']
]);
This query leads us to the following output:
[0] => Array
(
[Tag] => Array
(
[tag] => walls.io
)
[0] => Array
(
[count] => 15
)
)
As you can see, the query returns the results in a "somehow wrong" nesting. The "count" field is unfortunately put into a pseudo [0]-array.
IIRC, CakePHP uses internally a syntax like Tag__field for correctly nesting virtual fields.
When changing the code to the Model__-syntax, the problem stays the same:
return $this->find(
'all', [
'fields' => ['DISTINCT Tag.tag', 'COUNT(Tag.tag) as Tag__count'],
'group' => ['Tag.tag'],
'order' => ['COUNT(Tag.tag)' => 'DESC']
]);
Output:
[0] => Array
(
[Tag] => Array
(
[tag] => walls.io
)
[0] => Array
(
[Tag__count] => 15
)
)
Workaround 1: array_map
CakePHP pros: Is there a better/more elegant solution than manually mapping the array after the select statement?
$tags = array_map(function($tag) {
$tag['Tag']['count'] = $tag[0]['count'];
unset($tag[0]);
return $tag;
}, $tags);
Workaround 2: virtual field
As described above, the usage of a virtual field might solve this problem:
$this->virtualFields = ['count' => 'COUNT(Tag.Tag)'];
return $this->find(
'all', [
'group' => ['Tag.tag'],
'order' => [$this->getVirtualField('count') => 'DESC']
]);
Unfortunately, with this solution, it's not possible to specify ANY fields at all. only by completely leaving the "fields"-key, the nesting of the array works as expected. when selecting $fields = ['Tag.tag', $this->getVirtualField('count')] the nesting is wrong again.
CakePHP pros: Do you know a method, where the nesting is done right, even if you specify your own fields?
Looking at the CakePHP code, such a method does not exist.
Have a look at the file lib/Cake/Model/Datasource/Database/Mysql.php.
Find the method called: Mysql::resultSet( $results ); (around line 240).
That method maps the result to an array. To determine if a column is part of a table or not it uses PDOStatement::getColumnMeta(). For your "virtual column" that method will return an empty table and so the CakePHP code will put it separately, see the else branch
$this->map[$index++] = array(0, $column['name'], $type);
In order to avoid that else branch you would have to use Virtual fields, but then you run into the other problems that you have noticed.
So you are left with the array_map solution or you could try to overload that Mysql class and add your custom logic at how to identify where a column fits.
I've come across an odd problem using CakePHP 1.3 to find information. Let's use this dbschema as an example:
id is int(11) PRIMARY auto_increment
amount is float(10,2) NULL
status is ENUM(Completed, Removed, Pending)
id amount status
1 100.00 Completed
2 100.00 Removed
3 100.00 Completed
4 100.00 Completed
5 100.00 Pending
When using Cake's find to retrieve data from this table, I use this query:
$this->Testtable->find('all', array(
'conditions' => array(
'status LIKE ' => 'Removed',
'status LIKE ' => 'Pending',
'status LIKE ' => 'Completed'
)
))
Looking at this query, I would assume that Cake would return all rows that match all of those conditions (which is totally acceptable in SQL), however it only uses the last condition and returns WHERE status LIKE 'Completed'.
I ran a test doing this, which returned all rows correctly (I know it's a more "correct" way to do the query anyway):
'conditions' => array(
'status' => array('Removed', 'Pending', 'Completed')
)
Take the opposite for an example, I want to return all rows that aren't Removed or Pending:
'conditions' => array(
'status !=' => 'Removed',
'status !=' => 'Pending'
)
This query returns all rows with Completed and Removed, as it only listens to the last statement. I assume that this is happening because instead of concatenating these search conditions into the query, Cake is overwriting the conditions based on the "field" being status !=. I can prove this theory by adding a space after the != in either of those conditions, creating the desired result of only Confirmed records.
Can anybody tell me why Cake would do this? As this is a legitimate thing to do in SQL, I see no reason that Cake wouldn't allow you to do it. Does anybody know if this issue is fixed up in newer versions of Cake?
I suppose that this comes down to the fact that at the end of the day, I am reassigning the array value based on that key, and it's not actually CakePHP's fault at all. I had a look into Cake's model.php and found this:
$query = array_merge(compact('conditions', 'fields', 'order', 'recursive'), array('limit' => 1));
I ran a test:
$array = array(
'conditions' => array(
'test' => 'yes',
'test' => 'no'
)
);
$var = 'hello';
$c = compact('array', 'var');
print_r($c);
As mentioned above, compact is only receiving the value no from the test key. I assumed that the use of compact to merge variables/arrays into the query would recursively merge similar keys from the conditions array into the last specified, but it turns out that yes isn't even making it that far as it's being redefined on the spot.
I suppose this is a limitation of PHP rather than Cake, but it is still something that didn't occur to me and should be done differently somehow (if it hasn't already) in future.
Edit
I ran a couple more tests. I wrapped identical conditions in their own arrays, then compared them the way Cake's find functions would. Using compact (which Cake does) the arrays containing identical keys remain intact, however using array_merge, the first key is overwritten by the second. I guess in this case it's a very, very good thing that Cake uses compact instead of array_merge to merge its query criteria.
$array = array(
array('test' => 'yes'),
array('test' => 'no')
);
$m = array_merge($array[0], $array[1]);
$c = compact('array');
print_r($c);
print_r($m);
Result:
Array
(
[array] => Array
(
[0] => Array
(
[test] => yes
)
[1] => Array
(
[test] => no
)
)
)
Array
(
[test] => no
)
While this is obviously a simple problem in the way you fundamentally write PHP code, it wasn't inherently obvious while writing in Cake syntax that conditions would overwrite each other...
Basic PHP: Don't use the same array key twice
'conditions' => array(
'status LIKE ' => 'Removed',
'status LIKE ' => 'Pending',
'status LIKE ' => 'Completed'
)
should be
'conditions' => array(
'status LIKE' => array('Removed', 'Pending', 'Completed'),
)
Same for any other array key.
Note that some quick debugging of the array reveals this.
Please also see the tons of other stackoverflow questions with the same issue or other areas where basic research could have pointed you in this direction. Taking a look there first can help to resolve the issue in less time.
I am trying to do a batch_get_item to request multiple items from a table. I am following the PHP example in the DynamoDB documentation, but I am not getting the results I'm expecting.
Following is the code:
$batch_array = array ();
$batch_array[]= array ('HashKeyElement' =>
array( AmazonDynamoDB::TYPE_STRING => 'V1L3M5O5L1W8R5B6D2Q1S8V0B3R8M7A6R0X0'));
$options = array (
'RequestItems' => array(
'profile_dev' => array (
'Keys' => $batch_array
)
)
);
$result = $this->db->batch_get_item($options);
Instead of getting the data, I am getting a very long response, and I'm including the relevant information from the tail end of it:
[x-aws-body] => {"RequestItems":{"profile_dev":{"Keys":[{"HashKeyElement":{"S":"V1L3M5O5L1W8R5B6D2Q1S8V0B3R8M7A6R0X0"}}]}}} ) [body] => CFSimpleXML Object ( [__type] => com.amazon.coral.validate#ValidationException [message] => One or more parameter values were invalid: The provided key size does not match with that of the schema ) [status] => 400 ) )
The hashKey for this table is a string. It has a rangeKey, but I am using the hashKey so I can get all the rows matching the hashKey. What am I missing?
The DynamoDB documentation (and SDK samples) have colossal bugs in them. The documentation, and actual SDK code, make use only of the hashKeyElement, but in fact if a table has both a hashKey AND a rangeKey, both must be used.
When I used both the hashKey and the rangeKey, the call worked.
Get (or batch get) requires you to completely define the key of all items you are getting. If you want to retrieve all rows with the same hashKey using a single call, it seems like you're looking for Query.
You don't need to use BatchGet, you should be using Query. Here is an example using the PHP SDK to get all items with the HASH key 'YourHashKey' on table 'YourTable'
// Instantiate the class
$dynamodb = new AmazonDynamoDB();
$response = $dynamodb->query(array(
'TableName' => 'YourTable',
'HashKeyValue' => array( AmazonDynamoDB::TYPE_STRING => 'YourHashKey' ),
));
Reference: http://docs.amazonwebservices.com/amazondynamodb/latest/developerguide/LowLevelPHPQuerying.html
I can't figure out for the life of my to select from a collection with the or parameter. It's not working at all for me and I can't really find any documentation on it for php.
Here is my example code that doesn't return anything even though they exist in the collection:
$cursor = $products->find(
array(
'$or' => array(
"brand" => "anti-clothes",
"allSizes" => "small"
)
)
);
The $or operator lets you use boolean or in a query.
You give $or an array of expressions, any of which can satisfy the query.
You provided only one element in the array. Use:
find(array('$or' => array(
array("brand" => "anti-clothes"),
array("allSizes" => "small")
)));