Querying 🏹

Table Of Contents

• Find
  • Query Documents
  • Query a Specific Document
  • Query a Specific Document with a Specific Attributes
  • Query a Specific Document with a Specific Attributes to Include and Exclude
  • Query a Specific Document with a Regex
• Limit

Find

Query Documents

// Find All Documents in "recipes" Collection
> db.recipes.find()

// Return Document(s) with an ID (it contains an encoded daytime) 
{ "_id" : ObjectId("62a29c6859e7529499943d7c"), "title" : "Tacos", "desc" : "Yummie tacos", "cook_time" : 20 }

// Find All Documents in "recipes" Collection and Display it with Pretty Print
> db.recipes.find().pretty()

// Return Document(s) and Display it Pretty 
{
        "_id" : ObjectId("62a29c6859e7529499943d7c"),
        "title" : "Tacos",
        "desc" : "Yummie tacos",
        "cook_time" : 20
}

Query a Specific Document

> db.recipes.find({"title" : "Tacos"}).pretty();
{
        "_id" : ObjectId("5e5e9c470d33e9e8e3891b35"),
        "title" : "Tacos",
        "calories_per_serving" : 210,
        "cook_time" : 20,
        "desc" : "Classic Mexican tacos",
        "directions" : [
                "Brown beef",
                "Add taco seasoning and water, mix",
                "Bring to boil",
                "Lower heat to simmer 5-10 minutes until desired consistency",
                "Put meat in tacos"
        ],
        "ingredients" : [
                {
                        "name" : "ground beef (lean)",
                        "quantity" : {
                                "amount" : 1,
                                "unit" : "lbs"
                        }
                },
                {
                        "name" : "taco seasoning",
                        "quantity" : {
                                "amount" : 2,
                                "unit" : "oz"
                        }
                },
                {
                        "name" : "corn hard tacos",
                        "quantity" : {
                                "amount" : 12,
                                "unit" : "oz"
                        }
                }
        ],
        "likes" : [
                1,
                415
        ],
        "likes_count" : 2,
        "prep_time" : 10,
        "rating" : [
                4,
                4,
                3,
                4,
                2,
                5,
                2,
                2,
                4,
                5
        ],
        "rating_avg" : 3.5,
        "servings" : 4,
        "tags" : [
                "mexican",
                "quick",
                "easy",
                "ground beef"
        ],
        "type" : "Dinner"
}

Query a Specific Document with a Specific Attributes

• By default, the query result returns all document fields. It is possible to specify the fields you want. To do so, you need to provide a second parameter to find (include attribute = 1).

// Find a document with title "Tacos". The result document should return only "title" attribute. 
> db.recipes.find({"title" : "Tacos"}, {"title" : 1}).pretty();

{ "_id" : ObjectId("5e5e9c470d33e9e8e3891b35"), "title" : "Tacos" }

// Find a document with title "Tacos". The result document should return "title" and "type" attributes. 
> db.recipes.find({"title" : "Tacos"}, {"title" : 1, "type" : 1}).pretty();
{
        "_id" : ObjectId("5e5e9c470d33e9e8e3891b35"),
        "title" : "Tacos",
        "type" : "Dinner"
}

Query a Specific Document with a Specific Attributes to Include and Exclude

• By default, the query result returns all document fields. It is possible to specify the fields you want. To do so, you need to provide a second parameter to find (include attribute = 1, exclude attribute = 0).

// Find a document with title "Tacos". The result document should return "title" and "type" attributes and exclude the Id. 
> db.recipes.find({"title" : "Tacos"}, {"title" : 1, "type" : 1, "_id" : 0}).pretty();

{ "title" : "Tacos", "type" : "Dinner" }

Query a Specific Document with a Regex

// Find a document with title based on a regex. The result documents should return "title" attribute. 
> db.recipes.find({"title" : {$regex : /taco/i }}, {"title" : 1});
{ "_id" : ObjectId("5e6fd805fa98021236426a24"), "title" : "Chicken Soft Tacos" }
{ "_id" : ObjectId("5e5e9c470d33e9e8e3891b35"), "title" : "Tacos" }

Limit

The limit() function in MongoDB is used to specify the maximum number of results to be returned.

> db.recipes.find({ "title" : {$regex : /taco/i} }, {"title" : 1}).limit(1).pretty();
{
        "_id" : ObjectId("5e6fd805fa98021236426a24"),
        "title" : "Chicken Soft Tacos"
}