My Exam 3 review notes for CIS4301 Spring 2014. This repository is here in an effort to help crowdsource exam review notes. Please submit pull requests to improve/add content.
##Topics To-Do
Thanks to Eric Gross for the topic list:
- JDBC
- Cursor in database.
- It is an iterator, also the same as the ResultSet(Java).
- PreparedStatements are faster because it's already partially parsed, and all you have to do is just insert a value where the '?' is placed within the prepared statement.
- Reflection Statement - Where the driver is.
- Cursor in database.
- Query with EXPLAIN & ANALYZE
- EXPLAIN gives the tree of the query plan.
- Start-up Cost | Estimated Cost | rows & width in bytes.
- ANALYZE gives back the analysis of the query plan.
- EXPLAIN gives the tree of the query plan.
- Know steps of K-Means
- Choose K - # of clusters.
- Randomly place centroids.
- Assign Points to centroids.
- Average of all the points for each centroid.
- Update the location of centroids.
- Repeat 3 - 6 until no more updates on centroids.
- Know use-cases of K-Means.
- Group together data with similar information and how they're relevant.
- Can group what type of data is being grouped togehter
- i.e., types of dogs, age and salary of people.
- Things within a cluster are similar.
- Things between clusters are dis-similar.
- When do you have the best K?
- Check the average distance between the points and the centroids.
- If the distances withinthe sae cluster are close, then it's a good K.
- Find the K that is right at the downslope of the curve.
##Topics Done
Please update when you submit a pull request with new information.
-
HTML
- FORMS
- SUBMIT
- USING A METHOD (GET & POST)
- Know the difference between the two.
- Use POST for putting stuff into a database.
- Use GET to just retrieve data from database.
- Users can easily change GET requests in the URL.
- GET requests store the information in the URL.
- #/some_URL - Takes you to the div(id = 'some_URL')
-
Map Reduce
- Know the stages.
- Map
- Reduce
- Shuffle
- Know what a functional map-reduce is.
- Takes a function and does a map reduce of it.
- Know the stages.