The primary contributors to date have been:.
If you are one of them, and not on this list, please contact Brad or Steven. See more detailed instructions on the FAQ page. Jump to: navigation , search. When will the new version be released? Hard to say. We all have day jobs and do this as an altruistic endeavor to make the world a better place. Making progress as fast as we can I only have a few minutes per month to help! How do I get involved?
Fast, beautiful apps
Please join the mail list , introduce yourself, go find something that needs fixing in the GitHub issue list. Not familiar with git? Get the Dev Guide on GitHub and make edits on your machine, email me your work and I will commit it to the project blaming you in the commit message via a parseable format that I can extract for attribution.
I really want to help big time. Please join the mail list , introduce yourself, go find something that needs writing or missing on GitHub , write the first draft and mail it to us on the mail list. We'll take it from there! How do I get commit privileges on GitHub? Rinse and repeat!
You do not have to be a security expert in order to contribute. The client then makes an HTTP request to the web server, including this identifier.
The web application can then push messages addressed to the client to a local interface of the relay server, which relays them over the Flash socket. As mentioned previously, there are many pieces to the web development puzzle, and not every qualified website developer will necessarily be skilled at all of them. Accordingly, many web developers may focus predominantly on the client side and will therefore have little expertise in the database domain.
However, efficient database design, access, and manipulation is fairly central to the performance of most web-based systems and, as such, a web developer with strong database expertise can be extremely valuable to your project. Q: What does it mean to normalize a database? How does one go about doing it? Describe a potential consequence of database normalization.
Ionic - Cross-Platform Mobile App Development
Database normalization is the process of organizing the fields and tables of a relational database to minimize redundancy. Normalization usually involves dividing large tables into smaller and less redundant tables and defining relationships between them. The objective is to isolate data so that additions, deletions, and modifications of a field can be made in just one table and then propagated through the rest of the database using the defined relationships.
A good way to begin to normalize your database is to first assess it against the normal forms of relational database theory.
A database that satisfies the requirements of a certain level, must also satisfy all the previous levels. The first three of these levels are the ones most commonly used and are as follows:. Assessing the compliance of your database with these normal forms can help identify and eliminate redundancies in your data model that can make it more efficient and incidentally, this can also be beneficial in terms of determining the granularity of the entries in your cache.
But as with anything in life, normalization does have its costs.
The very act of spreading your data across several tables will likely require an increased number of table joins in your queries, which can also complicate your queries and possibly even your code. It also eliminates some potentially beneficial indexing scenarios, since data from multiple tables cannot be indexed. Retrieval can become expensive as well, and much more complicated when trying to filter or sort data in one table based on the values in another. That said, the best approach is usually a mix of these and other architectural patterns that suit the specific requirements of your application.
What are some of their relative advantages and disadvantages? In any tree-based index, records are stored in locations called leaves. The starting point is called the root. The maximum number of children per node is called the order of the tree. The maximum number of access operations required to reach the desired leaf data stored on the leaf is called the depth level.
A key in a node can lead to a node where all the keys are less that its value to its left, or to a node where all the keys are greater than its value to its right. The B-tree is a generalization of a binary search tree in that a node in a B-Tree is allowed to have more than two children. B-Tree indices help find information quickly by successively narrowing down data by assessing ranges of values stored in the node keys nodes in the index contain keys and pointers to their child nodes. A B-Tree search starts at the root node and compares the range of keys in each child node against the key value being sought.
When it finds the node whose range contains the desired key value, that node is selected and then its child nodes are assessed. This occurs until the process reaches the leaf pages where there are pointers to the actual data. In a Hash Index , the values of the indexed column are run through a hash function to generate a location identifier for each key in the hash table.
Hash indexes are fast because the exact location of the bucket is known and the hash keys are ordered sequentially. Hash indices work well, but only for purposes of equality comparisons. In contrast, B-Tree indices allow for much more flexibility in terms of what you can search for. Partial values and ranges of values are easily handled, all with roughly the same speed in a non-join search. It largely depends on the nature and structure of your data.
Q: Briefly describe and compare relational, document, and graph databases. Relational databases organize data into 2-dimensional tables and supports the notion of linking their contents based on known relationships. These relationships facilitate and simplify the integration and retrieval of data from multiple tables with a single query. While relational databases were a significant advance when they were originally introduced in the s, new ways of storing data have since emerged that allow data to be grouped together more naturally and logically, and that loosen the restrictions on database schema.
In a document database, everything related to a database object is encapsulated together. Storing data in this way has the following advantages:. Documents are independent units which makes performance better related data is read contiguously off disk and makes it easier to distribute data across multiple servers while preserving its locality.
Application logic is easier to write. Unstructured data can be stored easily, since a document contains whatever keys and values the application logic requires. In addition, costly migrations are avoided since the database does not need to know its information schema in advance. Document databases generally have powerful query engines and indexing features that make it easy and fast to execute many different optimized queries. Another relatively recent advance in database modeling came about with the advent of graph databases.
Graph databases, based on graph theory, use graph structures with nodes, edges, and properties to represent and store data. In a graph database, every element contains a direct pointer to its adjacent elements and no index lookups are necessary. Compared with relational databases, graph databases are often faster for associative datasets, and map more directly to the structure of object oriented applications. They can also scale more naturally to large datasets as they do not typically require expensive join operations.
As they depend less on a rigid schema, they are more suitable to manage ad-hoc and changing data with evolving schemas. Graph databases are an especially powerful tool for graph-like queries e. Conversely, relational databases are typically faster at performing the same operation on large numbers of data elements. Bear in mind that the questions provided herein are intended merely as a guide to help you find a web developer.
The questions and answers presented in this guide can be highly valuable in in your quest to hire a website developer, but are meant to augment an overall effective recruiting strategy, such as we describe in our post In Search of the Elite Few.