Technology Questions

The primary keys of entity tables are the foreign keys of dimension tables.

The Primary keys of fact dimensional table are the foreign keys of fact tablels.

- TABLES
- VIEWS
- INDEXES
- SYNONYMS
- SEQUENCES
- TABLESPACES

Aynchronous and Event Driven - All APIs of Node.js library area unit aynchronous that's non-blocking. It basically means that a Node.js based mostly server not waits for a API to return information. Server moves to next API when calling it and a notification mechanism of Events of Node.js helps server to induce response from the previous API decision.

Very Fast - Node.js library is very fast in execution of code.

Single Threaded but highly Scalable - Node.js uses a single threaded model with event looping. Node.js uses a single threaded program and same program can services much larger number of requests than traditional server like open source.

No Buffering - Node.js applications never buffer any data. These applications simply output the data in faster.

The Java programming language provides a system-level thread to track memory allocation.

Garbage collection has the following characteristics:

• Checks for and frees memory no longer needed

• Is done automatically

• Can vary dramatically across JVM implementations

-  The process of having a copy of redo log files is called mirroring.
-  It is done by creating group of log files together. This ensures that LGWR automatically writes them to all the members of the current on-line redo log group.
-  In case a group fails, the database automatically switches over to the next group. It diminishes the performance.

An unspecified passive open has the server waiting for a connection request from a client. A fully specified passive

open has the server waiting for a connection from a specific client.

Language Integrated Query (LINQ) adds the ability to query objects using .NET languages. The LINQ to SQL object/relational mapping (O/RM) framework provides the following basic features:

- Tools to create classes (usually called entities) mapped to database tables

- Compatibility with LINQ's standard query operations

- The DataContext class, with features such as entity record monitoring, automatic SQL statement generation, record concurrency detection, and much more

At the time of updating the data warehouse, a lookup table is used. When placed on the fact table or warehouse based upon the primary key of the target, the update is takes place only by allowing new records or updated records depending upon the condition of lookup.

The materialized views are aggregate tables. It contains summarized data. For example, to generate sales reports on weekly or monthly or yearly basis instead of daily basis of an application, the date values are aggregated into week values, week values are aggregated into month values and month values into year values. To perform this process aggregate function is used.