In MongoDB, the $ne aggregation pipeline operator compares two values and returns either true or false, depending on whether the two values are not equivalent.
MongoDB
MongoDB $in Aggregation Pipeline Operator
In MongoDB, the $in aggregation pipeline operator returns a boolean indicating whether a specified value is in the array.
The $in aggregation pipeline operator is not to be confused with the $in query operator, which selects the documents where the value of a field equals any value in the specified array.
MongoDB $in Query Operator
In MongoDB, the $in query operator selects the documents where the value of a field equals any value in the specified array.
The $in query operator is not to be confused with the $in aggregation pipeline operator, which returns a boolean indicating whether a specified value is in the array.
2 Ways to Delete a Database in MongoDB
If you no longer need a database in MongoDB you can delete it.
Technically speaking, the term normally used for deleting a database is drop. To drop a database is to delete it.
In any case, below are two ways you can drop/delete a database in the mongo shell.
MongoDB $gte Aggregation Pipeline Operator
In MongoDB, the $gte aggregation pipeline operator compares two values and returns either true or false, depending on whether or not the first value is greater than or equal to the second value.
MongoDB $ifNull
In MongoDB, $ifNull is an aggregation pipeline operator that allows you to specify a value to use in place of null.
The way that it works is, you provide an expression and a replacement expression. If the expression evaluates to a non-null value, that expression is returned. But if the expression evaluates to a null value, $ifNull returns the value of the replacement expression.
A null value includes instances of undefined values or missing fields.
MongoDB $gt Aggregation Pipeline Operator
In MongoDB, the $gt aggregation pipeline operator compares two values and returns either true or false, depending on whether or not the first value is greater than the second value.
MongoDB $lte Aggregation Pipeline Operator
In MongoDB, the $lte aggregation pipeline operator compares two values and returns either true or false, depending on whether or not the first value is less than or equal to the second value.
MongoDB $lt Aggregation Pipeline Operator
In MongoDB, the $lt aggregation pipeline operator compares two values and returns either true or false, depending on whether or not the first value is less than the second value.
How to Prettify Exported MongoDB Documents in mongoexport
When you use mongoexport to export documents in MongoDB, you have the option of “prettifying” them.
By this I mean, instead of the document being presented on one long line, it instead includes line breaks, indents, etc to make it easier to read.
To do this in mongoexport, use the --pretty parameter.