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Query Collection

This node is used to access a collection of Models in the cloud store. To learn more about Models and Collections check out the guide.

INPUTS

General

Collection Name
The name of the Collection that this node will access.

Use Limit
Enables or disables limiting the number of result fetched from the cloud store.

Limit
Specifies the maximum number of Models that will be fetched from the cloud store.

Skip
Specifies a number of Models that will be skipped when returning the result of the query. This is typically used together with limit to achieve pagination.

Filter
The type of filter to choose, can be Simple or Advanced. See below for more details.

Filter

By default the Query Collection will fetch all Models, you can however add a filter. You can choose from a simple filter where you can filter on one or more Model properties, or a more advanced JSON based filter syntax. More on that below, first the simple filter type.

Add a property that you want to filter on.

For each filter property you can now specify:

Type
The type you want for the filter, can be Number, String or Boolean.

Op
The available operations of the filter depend on the type that is set.

  • Equals Include in filter if the property equals the provided value. Available for all types.
  • Not Equals Include in filter if the property does NOT equal the provided value. Available for all types.
  • Greater than Include in filter if the property is greater than the provided value. Only available if type is Number.
  • Less than Include in filter if the property is less than the provided value. Only available if type is Number.
  • Greater than or equal Include in filter if the property is greater than or equal to the provided value. Only available if type is Number.
  • Less than or equal Include in filter if the property is less than or equal to the provided value. Only available if type is Number.

Value
The value used to test against in the filter operation.

Sort

By default the Query Collection does not return the result of a fetch sorted. You can specify sorting. Like filters you add which properties you want to sort on.

For each property you can choose the sorting order.

Advanced filters

If you choose Advanced as filter type you will get the option to specify a filter script. This is regular javascript code but you need to end the script by calling the where function with the filter definition provided. This is done using the following syntax:

where({ 
    Completed:{equalTo:true} 
})

The above filter will return all models in the collection that has the Completed property true. You can select from a number of operators:

  • lessThan Less Than
  • lessThanOrEqualTo Less Than Or Equal To
  • greaterThan Greater Than
  • greaterThanOrEqualTo Greater Than Or Equal To
  • notEqualtTo Not Equal To
  • containedIn Contained In
  • notContainedIn Not Contained in
  • exists A value is set for the key

For instance, to filter on if a certain property (in this example Letter) is one of many possible values:

where({ 
    Letter:{containedIn:['A','B','C']} 
})

Or to filter all models that have a value set for a specific property:

where({ 
    Letter:{exists:true}
})

You can also combine these filters into expressions using and and or, for instance:

where({ 
    and: [ 
        {ZipCode:{exists:true}}, 
        {Score:{greaterThan:10}} 
    ]
})

You can also use the matchesRegex operator to filter by regular expression, this is generally slow and not recommended for large sets. Learn more here

where({ 
    SomeString:{matchesRegex:"pattern", options:'i'} 
})

As mentioned above the filter script is a javascript function so you can provide javascript code if you like:

where({ 
    SomeDate:{equalTo:(new Date()).toISOString()} 
})

You can also specify variables instead of explicitly specifying the filter values, this will create an input port on the Query Collection node that can then be connected to. You specify variables using the $ syntax, it must be a javascript compatile name. The filter below will create an input called MyStringInput.

where({ 
    SomeString:{equalTo:$MyStringInput} 
})

You can also do text search in strings. This will create an index in the database and text search only works on one property so you have to choose wisely. Also text search matches whole words and must be the first filter in an and or or sequence.

where({ 
    SomeString:{text:{search:$MyStringInput}}
})

You can also toggle case sensitivity for text searches.

where({ 
    SomeString:{text:{search:{
        term:$MyStringInput,
        caseSensitive:true
    }}}
})

If you need to match the Id of models in the collection you need to use the special operation:

where({ 
    idEqualTo:$TheModelId
})

In the above filter you can connect a Model Id output to the TheModelId parameter to fetch just one specific object. You can also request a set of object based on their Id.

where({ 
    idContainedIn:[$FirstObjectId, $SecondObjectId]
})

Some properties in your Models can be of Pointer type, that means that they reference another object with a specific Id and Collection. If you want to filter out models that point to a specific model, use this syntax. Let's say you have a collection of Post models, each have a set of Comment models where each Comment points back to it's owning Post via the Owner property. The filter below will find all Comments for a Post given that you provide the post id.

where({ 
    Owner:{pointsTo: $MyPostId }
})

You can also provide an array if you want to find Comments that are related to a set of Post models.

where({ 
    Owner:{pointsTo: [$MyFirstPostId, $MySecondPost] }
})

Don't forget that you need to send a signal to Fetch to perform a new fetch with a new filter if any of the filter inputs have changed.

Models also support many-to-many relationships via Relations, check out the guide here for more information. You can filter our all models in the collection you are querying that are related to a specific model via a Relation with a given key using:

where({ 
    relatedTo:{id: $MyObjectWithARelation, key: "the-relation-key"}
})

Sorting in advanced filters

To specify the sort order when using advanced filter you run a function called sort in the filter script.

where({ 
    // You where filter here
})

sort(['createdAt'])

The sort function takes an array with strings specifying the names of the properties you want to sort by. You can prefix the property name with "-" to specify that you want to sort in descending order instead of the default ascending order.

sort(['-Age','createdAt'])

OUTPUTS

General

Name
The identifier of this Collection. This is the collection name.

Result
An array of the items fetched from the cloud store.

Count
The count of the retuned array from the cloud store.

First Item Id
The Id of the first model or undefined.

Events

Modified
Event signal sent when the collection is modified locally, e.g. when a Model that has previously been fetched is deleted.

Fetched
Event signal sent when a Fetch is successful.

Failure
Sent when a Fetch has failed.

Error
A string with a message indicating the reason for failure.