Query method
3 minute read
The document describes the query
method, parameters, and output.
Method
query
- Queries for particular model records.
Parameters
The query
method parameters are:
Parameter | Type | Default | Description | Configuration selection |
---|---|---|---|---|
limit | integer | 10 | The number of records to fetch. | Selector, Number |
order | object | - | A dictionary of key-value pairs describing the field(s) for sorting. The field name is the key and the value is set to either -1 for ascending order or 1 for descending order. | Selector, Object |
sel | object | - | A dictionary of key-value pairs describing which fields to include in the query results. The field name is the key and the value is set to 1. | Selector, Object |
skip | integer | - | The number of records to skip. | Selector, Number |
unsel | object | - | A dictionary of key-value pairs describing which fields to exclude from the query results. The field name is the key and the value is set to 1. | Selector, Object |
where | string | - | The JSON-encoded object specifying field constraints. The field name is the key and the value is the constraint statement or value. | Selector, String |
All parameters can be enabled or disabled.
Where parameter
The query
method where
parameter operators are:
Name | Description | Syntax |
---|---|---|
$eq | Query records that are equal to a specified value. The $eq operator matches records where the value of a field equals the specified value. The $eq expression is equivalent to { field: <value> } . |
{ < field >: { $eq : < value > } } |
$ne | Query records that are not equal to a specified value. The $ne operator selects the records where the value of the field is not equal to the specified value . This includes records that do not contain the field . |
{field: {$ne: value} } |
$gt | Query records that are greater than a specified value. The $gt operator selects those records where the value of the field is greater than the specified value . |
{field: {$gt: value} } |
$lt | Query records that are less than a specified value. The $lt operator selects the records where the value of the field is less than the specified value . |
{field: {$lt: value} } |
$gte | Query records that are greater than or equal to a specified value. The $gte operator selects the records where the value of the field is greater than or equal to a specified value . |
{field: {$gte: value} } |
$lte | Query records that are less than or equal to a specified value. The $lte operator selects the records where the value of the field is less than or equal to the specified value . |
{ field: { $lte: value} } |
$in | Query records that match any of the values specified in an array. The $in operator selects the records where the value of a field equals any value in the specified array. |
{ field : { $in : [ < value1 > , < value2 > , ... < valueN > ] } } |
$nin | Query records that do not match any of the values specified in an array. The $nin operator selects the records where the field value is not in the specified array or the field does not exist. |
{ field: { $nin: [ <value1>, <value2> ... <valueN> ]} } |
Outputs
The query
method output is:
Output | Type | Description | Save output value as: |
---|---|---|---|
next | array | Successfully queried the record. | $.queried |
Last modified October 5, 2021: Fix all sections of the docs to be compliant. (#24) (b0bcdbc)