MongoDB Grand Rapids RUG


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Don't know if it is worthwhile without me explaining the points but I'll post them anyway.

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  • High volume, lower value. No transactions. Drivers for several languages. All network based for speed (instead of REST).
    Uses BSON for storage of objects and for building queries. Binary-encoded serialization like JSON. Allows for some representations that JSON does not.
    BSON seems “blob-like” but mongo speaks BSON and can “reach in” to documents.
    Powerful query language, with query optimizer. You can drop down to javascript also.
    Supports master/slave.

  • Talk about harmony and how we are abusing mysql for key/value meta data on pages.
    Talk about capped collections and how they work like memcache. Also, how they are used for replication even.

  • _id’s can be any type, just have to be unique in collection
  • find always returns a cursor that you can keep iterating through

  • Don’t have to typecast with mongo as it “knows” types but form submissions are always strings so typecasting has its benefits.
    * note required
    * note length
    * note numeric
    * note index
  • multikey - automatically index arrays of object values
    ensure index on tags or _keywords

  • MongoDB Grand Rapids RUG

    1. 1. INTRO
    2. 2. INTRO • Built For Speed • Document/Collection Oriented • Dynamic Queries and Indexes • Replication and Failover
    3. 3. GREAT FOR • Websites • Caching • High volume, low value • High scalability • Storage of program objects and json
    4. 4. NOT AS GREAT FOR • Highly transactional • Ad-hoc business intelligence • Problems requiring SQL
    5. 5. INSTALLATION • mkdir -p /data/db • download pre-built for OSX and unzip to /usr/local/ • cp -R /usr/local/pathtomongo/bin /usr/local/bin
    6. 6. DATABASE • same concept as mysql • made up of collections
    7. 7. COLLECTION • Think table, but with no schema • For grouping documents into smaller query sets (speed) • Eachtop level entity in your app would have its own collection (users, articles, etc.) • Indexable by one or more key
    8. 8. DOCUMENT • Stored in a collection, think record or row • Can have _id key that works like primary keys in MySQL • Two options for relationships: subdocument or db reference
    9. 9. QUERYING • db.collection.find({‘first_name’: ‘John’}) # finds all Johns • db.collection.find({‘first_name’: /^J/}) # regex • db.collection.find_first({‘_id’:1}) # finds first with _id of 1 • db.collection.find({‘age’: {‘$gt’: 21}}) # finds possible drinkers • db.collection.find({‘author.first_name’:‘John’}) # subdocument • db.collection.find({$where:‘this.age >= 6 && this.age <= 18’})
    10. 10. MORE QUERYING • $in, $nin, $all, $ne, $gt, $gte, $lt, $lte, $size, $where • :fields (like :select in active record) • :limit, :offset for pagination • :sort ascending or descending [[‘foo’, 1], [‘bar’, -1]] • count and group (uses map/reduce)
    11. 11. HOW DO YOU USE IT WITH RUBY • mongo-ruby-driver driver • activerecord adapter activerecord-mongo-adapter • mongorecord activerecord-ruby
    12. 12. NUNEMAPPER (MONGOMAPPER) • Mongo is not MySQL • DSL for modeling domain should also teach you Mongo • It sounded fun • Almost finished and sitting in private GitHub repo
    13. 13. FEATURES • Typecasting • Create and Update with single or multiple • Callbacks(ActiveSupport Callbacks) • Delete and Destroy and _all counterparts • Validations (using my fork of validatable) • Find: id, ids, :all, :first, :last • Connection and database • Associations (incomplete) can differ per document
    14. 14. EXAMPLE class User include MongoMapper::Document key :name, String, :required => true, :length => 5..100 key :email, String, :required => true, :index => true key :age, Integer, :numeric => true key :active, Boolean, :default => true one :address many :articles end class Address include MongoMapper::EmbeddedDocument key :street, String key :city, String key :state, String, :length => 2 key :zip, Integer, :numeric => true, :length => 5 end
    15. 15. RANDOM AWESOMENESS • Capped collections (think memcache, actually used for replication) • Upserts db.collection.update({‘_id’:1}, {‘$inc’:{‘views’:1}}) • Multikeys (think tagging and full text search) • GridFS and auto-sharding
    16. 16. John Nunemaker Links
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