In this part of my MongoDB tutorial I cover insert, understanding id keys, find, update, remove, drop, searching for ranges, and numerous ways to query your database. If you haven’t watched part 1 definitely watch it first because I showed how to set up everything in that tutorial.
Like always, all of the code follows the video below. It is best to have it in front of you as you watch so that you can refer to the documents stored in the database.
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Code From the Video
---------- Inserting, Updating and Deleting Documents ----------
1. We covered inserting like this db.testdb.insert({"name" : "Barry Bonds"})
2. We can also insert arrays of documents
db.testdb.insert([{"name" : "Babe Ruth"}, {"name" : "Hank Aaron"}])
3. Object IDs or _id is a unique key made up of 24 hexadecimal numbers, or 2 digits for each byte
a. The first 4 bytes make up a time stamp
b. The next 3 represent a unique id for the computer that generated the id
c. The next 2 bytes represent a unique id based on the process for the computer
d. The last 3 bytes are incrementing numbers for each generated id
4. Delete a document like this : db.testdb.remove({"name" : "Babe Ruth"})
5. We can receive well formatted results with pretty()
db.testdb.find().pretty()
6. We can update a document like this
db.testdb.update({"name" : "Hank Aaron"},
{$set:{"name" : "Hank Louis Aaron", "Home Runs" : 755}})
7. You can update multiple documents like this
a. db.testdb.insert([{"name" : "Babe Ruth", "Hall Of Fame" : "Inductee"},
{"name" : "Ty Cobb", "Hall Of Fame" : "Inductee"},
{"name" : "Walter Johnson", "Hall Of Fame" : "Inductee"},
{"name" : "Christy Mathewson", "Hall Of Fame" : "Inductee"},
{"name" : "Honus Wagner", "Hall Of Fame" : "Inductee"}])
b. db.testdb.update({"Hall Of Fame" : "Inductee"},
{$set:{"Hall Of Fame" : "Inducted in 1936"}}, {multi:true})
8. You can also replace a document like this
db.testdb.save({
"Name" : "Hank Louis Aaron",
"Home Runs" : 755,
"Hall Of Fame" : "Inducted in 1988"})
9. We can increment a value in a document like this
db.testdb.update({"name" : "Hank Louis Aaron"},
{"$inc" : {"Home Runs" : 1}})
10. You can decrement like this
db.testdb.update({"name" : "Hank Louis Aaron"},
{"$inc" : {"Home Runs" : -1}})
11. We can multiply values
db.testdb.update({"name" : "Hank Louis Aaron"},
{"$mul" : {"Home Runs" : 1.04}})
12. We can add to an array or create one if it doesn't exist
db.testdb.update({"name" : "Barry Bonds"},
{"$push" : {"Records" :
{"Single Season HRs" : 73,
"HRs Career" : 762,
"Walks" : 232}}})
13. You can push multiple values in one operation
db.testdb.update({"name" : "Barry Bonds"},
{"$push" : {"Batting Average" : {"$each" : [.223, .261, .283, .248, .301]}}})
14. You can set the maximum number of items an array can have with slice
db.testdb.update({"name" : "Barry Bonds"},
{"$push" : {"Best Home Run Years" : {"$each" : [45, 45, 46, 46, 49, 73],
"$slice" : -5}}})
15. addToSet adds a value only if it doesn't already exist
db.testdb.update({"name" : "Barry Bonds"},
{"$addToSet" : {"Best Home Run Years" : 47}})
16. Remove the last item added to an array
db.testdb.update({"name" : "Barry Bonds"},
{"$pop" : {"Best Home Run Years" : 1}})
17. You can also remove the first item
db.testdb.update({"name" : "Barry Bonds"},
{"$pop" : {"Best Home Run Years" : -1}})
18. Pull can remove a specific value
db.testdb.update({"name" : "Barry Bonds"},
{"$pull" : {"Best Home Run Years" : 73}})
---------- Querying the Database ----------
1. db.testdb.find() is the most basic query which returns everything
2. You can restrict the results by passing key value pairs
db.testdb.find({"name" : "Ty Cobb"})
3. Drop the collection with db.testdb.drop() and Insert
db.testdb.insert([{"name" : "Dale Cooper", "street" : "123 Main St", "city" : "Yakima", "state" : "WA", "dob" : new Date(1959, 2, 22), "sex" : "M", "gpa" : 3.5, "status" : "student", "tests" : [10, 9, 8], "contact info" : {"email" : "dc@aol.com", "phone" : "792-223-8901"}},
{"name" : "Harry Truman", "street" : "202 South St", "city" : "Vancouver", "state" : "WA", "dob" : new Date(1946, 1, 24), "sex" : "M", "gpa" : 3.4, "status" : "student", "tests" : [8, 9, 8], "contact info" : {"email" : "ht@aol.com", "phone" : "792-223-9810"}},
{"name" : "Shelly Johnson", "street" : "9 Pond Rd", "city" : "Sparks", "state" : "NV", "dob" : new Date(1970, 12, 12), "sex" : "F", "gpa" : 2.9, "status" : "dropout", "tests" : [10, 8, 0], "contact info" : {"email" : "sj@aol.com", "phone" : "792-223-6734"}},
{"name" : "Bobby Briggs", "street" : "14 12th St", "city" : "San Diego", "state" : "CA", "dob" : new Date(1967, 5, 24), "sex" : "M", "gpa" : 2.0, "status" : "student", "tests" : [5, 4, 6], "contact info" : {"email" : "bb@aol.com", "phone" : "792-223-6178"}},
{"name" : "Donna Hayward", "street" : "120 16th St", "city" : "Davenport", "state" : "IA", "dob" : new Date(1970, 3, 24), "sex" : "F", "gpa" : 3.7, "status" : "student", "tests" : [10, 8, 8], "contact info" : {"email" : "dh@aol.com", "phone" : "792-223-2001"}},
{"name" : "Audrey Horne", "street" : "342 19th St", "city" : "Detroit", "state" : "MI", "dob" : new Date(1965, 2, 1), "sex" : "F", "gpa" : 3.0, "status" : "student", "tests" : [9, 9, 8], "contact info" : {"email" : "ah@aol.com", "phone" : "792-223-2002"}},
{"name" : "James Hurley", "street" : "2578 Cliff St", "city" : "Queens", "state" : "NY", "dob" : new Date(1967, 1, 2), "sex" : "M", "gpa" : 2.9, "status" : "dropout", "tests" : [8, 9, 0], "contact info" : {"email" : "jh@aol.com", "phone" : "792-223-1890"}},
{"name" : "Lucy Moran", "street" : "178 Dover St", "city" : "Hollywood", "state" : "CA", "dob" : new Date(1954, 11, 27), "sex" : "F", "gpa" : 3.0, "status" : "student", "tests" : [9, 9, 8], "contact info" : {"email" : "lm@aol.com", "phone" : "792-223-9678"}},
{"name" : "Tommy Hill", "street" : "672 High Plains", "city" : "Tucson", "state" : "AZ", "dob" : new Date(1951, 12, 21), "sex" : "M", "gpa" : 3.7, "status" : "student", "tests" : [10, 9, 9], "contact info" : {"email" : "th@aol.com", "phone" : "792-223-1115"}},
{"name" : "Andy Brennan", "street" : "281 4th St", "city" : "Jacksonville", "state" : "NC", "dob" : new Date(1960, 12, 27), "sex" : "M", "gpa" : 2.5, "status" : "student", "tests" : [7, 9, 8], "contact info" : {"email" : "ab@aol.com", "phone" : "792-223-8902"}},
])
4. You can search for multiple key / value pairs by separating them with a comma
db.testdb.find({"state" : "WA", "sex" : "M"}).pretty()
5. You can limit the results returned by specifying the keys to return
db.testdb.find({"state" : "WA", "sex" : "M"}, {"name" : 1, "dob" : 1})
6. You can force the id to not be returned
db.testdb.find({"state" : "WA", "sex" : "M"}, {"name" : 1, "dob" : 1, "_id" : 0})
7. We can find people with a GPA in a range between 3.0 and 3.5
$lt = Less Then, $gt = Greater Then, $gte = Greater Then or Equal,
$lte = Less Then or Equal,
db.testdb.find({"gpa" : {"$gte" : 3.0, "$lte" : 3.5}}, {"name" : 1, "gpa" : 1, "_id" : 0})
8. We can search for people born after Jan 1, 1969
year1969 = new Date("01/01/1969")
db.testdb.find({"dob" : {"$gt" : year1969}}, {"name" : 1, "dob" : 1, "_id" : 0})
9. Return any student that is not a male
db.testdb.find({"sex" : {"$ne" : "M"}, "status" : "student"}, {"name" : 1, "_id" : 0})
10. Find GPAs of 3.4, 3.5, 3.6, or 3.7
db.testdb.find({"gpa" : {"$in" : [3.4, 3.5, 3.6, 3.7]}}, {"name" : 1, "_id" : 0})
11. Find all GPAs except for 3.4 - 3.7 that are active students
db.testdb.find({"gpa" : {"$nin" : [3.4, 3.5, 3.6, 3.7]}, "status" : "student"}, {"name" : 1, "_id" : 0})
12. To do an or check with multiple keys use $or
db.testdb.find({"$or" : [{"status" : "dropout"}, {"gpa" : {"$lt" : 3.0}}]}, {"name" : 1, "_id" : 0})
13. $not can be used to find every gpa not greater then 3.0
db.testdb.find({"gpa": {$not : {$gt : 3.0}}}, {"name" : 1, "_id" : 0})
a. You can just get the first 3 results with
db.testdb.find({"gpa": {$not : {$gt : 3.0}}}, {"name" : 1, "_id" : 0}).limit(3)
b. You could skip the first 2 with
db.testdb.find({"gpa": {$not : {$gt : 3.0}}}, {"name" : 1, "_id" : 0}).skip(2)
c. You can sort them by name
db.testdb.find({"gpa": {$not : {$gt : 3.0}}}, {"name" : 1, "_id" : 0}).sort({"name" : 1})
14. We can use a regular expression to search for everyone whose name starts with D
^ Match the beginning of the line
. Followed by * means match any character (.), any number of times (*)
$ Match the end of the line
db.testdb.find({"name" : /^D.*$/}, {"name" : 1, "_id" : 0})
15. We can check for every student that got a 0 on a test
db.testdb.find({"tests" : 0}, {"name" : 1, "_id" : 0})
16. Find students with a 10 and a 0 on tests
db.testdb.find({"tests" : {$all : [0, 10]}}, {"name" : 1, "_id" : 0})
17. Students that got a 10 on the first test (Arrays are 0 Indexed)
db.testdb.find({"tests.0" : 10}, {"name" : 1, "_id" : 0})
18. Find arrays of a certain size
a. First add an extra test to a student array
db.testdb.update({"name" : "Dale Cooper"}, {"$push" : {"tests" : 9}})
b. Check for students that have taken 4 tests
db.testdb.find({"tests" : {"$size" : 4}}, {"name" : 1, "_id" : 0})
19. Get the first 2 tests with $slice
db.testdb.find({"name" : "Dale Cooper"}, {"tests" : {"$slice" : 2}}).pretty()
20. Get the last 2 tests with $slice
db.testdb.find({"name" : "Dale Cooper"}, {"tests" : {"$slice" : -2}}).pretty()
21. Get the 2nd and 3rd tests with $slice by skipping the first and returning the next 2 in line
db.testdb.find({"name" : "Dale Cooper"}, {"tests" : {"$slice" : [1,2]}}).pretty()
22. Get the email for Lucy Moran with the dot operator
db.testdb.find({"name" : "Lucy Moran"}, {"name" : 1, "contact info.email" : 1, "_id" : 0})
23. Search for a match using the dot operator
db.testdb.find({"contact info.phone" : "792-223-1115"}, {"name" : 1, "_id" : 0})