WebFund 2014W Lecture 13

MongoDB

Data "types":

• Databases: sets of collections
• collections: sets of documents
• documents: sets of properties and values

Database operations:

• create/add a database
• drop/delete a database
• add a collection to a database
• remove a collection from a database
• select a collection to use

Collection operations:

• retrieve all documents
• retrieve specific documents matching a set of conditions
• add/insert a document
• remove/delete a document
• replace a set of document

Document operations:

• stored as a JS object with _id unique identifier
• set/change value of a property
• retrieve value of a property
• => key/value store or associative array

Transactions: (not in MongoDB)

• start a transaction
• specify queries to match documents/records
• specify changes to those documents/records
• commit changes if none of the specified data has been changed by others
• if others have changed documents/records, abort transactions and undo all changes
• Airline example: reserve seat and record payment
• If you want transactions, use SQL (e.g., PostgreSQL, Oracle, MySQL (sort of)), at the price of some performance

client-side JS

Key difference between client-side and server-side JS: THE DOM

• DOM = document object model
• tree representation of an HTML document
• with lots of access methods
• purpose: read and change HTML page under control of JS

jQuery

• standardized methods for accessing DOM (and other stuff)
• pattern: specify nodes => change nodes
• specify nodes via tag, id, & class (same identifiers used by CSS)