what is

How the arrayFilters Parameter Works in MongoDB

by

In MongoDB, when you update documents that contain arrays, you have the option of using the arrayFilters parameter.

The arrayFilters parameter allows you to specify an array of filter documents that determine which array elements to modify.

In the update document, use the $[<identifier>] filtered positional operator, which identifies the array elements that match the arrayFilters conditions for the update operation.

Read more

MongoDB $currentDate

by

In MongoDB, the $currentDate operator sets the value of a field to the current date.

It can be set as either a Date or a timestamp type. The default is Date.

$currentDate is an update operator, and can only be used when updating documents, not when inserting them (although it can be used in upsert operations).

Read more

MongoDB $toDate

by

In MongoDB, the $toDate aggregation operator converts a value to a date

$toDate takes any valid expression. If the expression can’t be converted to a date, it returns an error. If the expression is null or missing, it returns null.

Read more

MongoDB $mul

by

MongoDB has a $mul field update operator that allows you to multiply a value by a specific amount.

If the field doesn’t already exist, it is created and its value is set to zero (0) using the same numeric type as the multiplier.

Read more

MongoDB $inc

by

MongoDB has an $inc field update operator that allows you to increment a value by a specific amount.

You can use positive and negative values (i.e. to increment or decrement the value).

If the field doesn’t already exist, it is created with the specified value.

Read more

MongoDB $setOnInsert

by

The MongoDB $setOnInsert field update operator can be used to insert a specific value during an upsert.

If an update operation results in a new document being inserted (i.e. an upsert), then the $setOnInsert operator takes effect, otherwise it has no effect.

Read more

MongoDB $max

by

MongoDB has a $max operator that allows you to update the value of a field only if the specified value is greater than the current value of the field.

In other words, if the $max value is greater than the current value in the document, the $max value is used. Otherwise, the document’s value remains unchanged.

Read more

MongoDB $min

by

MongoDB has a $min operator that allows you to update the value of a field only if the specified value is less than the current value of the field.

In other words, if the $min value is less than the current value in the document, the $min value is used. Otherwise, the document’s value remains unchanged.

Read more

MongoDB $pop

by

In MongoDB, you can use the $pop operator to remove the first or last element from an array.

Use $pop in conjunction with a method such as update() to update the specified document with the change.

Use -1 to remove the first element, and 1 to remove the last.

Read more