Check if MongoDB database exists?

There are two possibilities to check whether the MongoDB database exists.

Case 1: The first possibility is that the MongoDB database exists, that is, a specific index is returned.

Case 2: The second possibility is that the MongoDB database does not exist, that is, index -1 is returned.

Note: Indexing starts from 0 like an array and ends with (N-1).

The syntax is as follows, used to check whether the MongoDB database exists.

db.getMongo().getDBNames().indexOf("yourDatabaseName");

Case 1: Let us implement the above syntax to check if the MongoDB database exists. Following is the query

db.getMongo().getDBNames().indexOf("test");

This will produce the following output

6

Looking at the above example output, we get 6 which means database "test" exists and it appears at index 6.

Now let's check all databases. Following is the query

> show dbs;

This will produce the following output

admin             0.001GB
config            0.000GB
local             0.000GB
sample            0.001GB
sampleDemo        0.000GB
studentSearch     0.000GB
test              0.009GB

Looking at the sample output above, the database "test" exists and has index 6.

Case 2: If the MongoDB database does not exist

> db.getMongo().getDBNames().indexOf("education");

The following is the output showing -1 because the database "education" does not exist

-1

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