Interview Questions

There are many algorithms that can be used to analyze the database to check the maintenance of all the data sets that are already present. The different types of cluster models include as follows:

- Connectivity models: these are the models that connect one cluster to another cluster. This includes the example of hierarchical clustering that is based on the distance connectivity of one model to another model. 

- Centroid models: these are the models that are used to find the clusters using the single mean vector. It includes the example of k-means algorithm.

- Distribution models: it includes the specification of the models that are statistically distributed for example multivariate normal distribution model.

- Density models: deals with the clusters that are densely connected with one another in the regions having the data space. 

- Group models: specifies the model that doesn’t provide the refined model for the output and just gives the grouping information

End of file  (10)

Duplicate key (22)

Record not found (23)

VSAM logic error  (90)

Open problem  (92)

Space problem (93)

setcookie('variable','value','time');
variable - name of the cookie variable
value     - value of the cookie variable
time       - expiry time

Example:
<?php
setcookie('Test',$i,time()+3600);
?>
Test - cookie variable name
$i - value of the variable 'Test'
time()+3600 - denotes that the cookie will expire after an one hour

Star schema: A highly de-normalized technique. A star schema has one fact table and is associated with numerous dimensions table and depicts a star.

Snow flake schema: The normalized principles applied star schema is known as Snow flake schema. Every dimension table is associated with sub dimension table.

Differences:

- A dimension table will not have parent table in star schema, whereas snow flake schemas have one or more parent tables.

- The dimensional table itself consists of hierarchies of dimensions in star schema, where as hierarchies are split into different tables in snow flake schema. The drilling down data from top most hierarchies to the lowermost hierarchies can be done.

Notices, Warnings and Fatal errors are the types of errors in PHP

Notices: 

Notices represents non-critical errors, i.e. accessing a variable that has not yet been defined. By default, such errors are not displayed to the user at all but whenever required, you can change this default behavior.

Warnings: 

Warnings are more serious errors but they do not result in script termination. i.e calling include() a file which does not exist. By default, these errors are displayed to the user.

Fatal errors: 

Fatal errors are critical errors i.e. calling a non-existent function or class. These errors cause the immediate termination of the script.

SELECT * FROM table_name ORDER BY column_name desc Fetch first 5 rows only;

1) List down usecases (taken from business cases) from function specs. For each use case write a test case and categorize them into sanity tests, functionality, GUI, performance etc. Then for each test case, write its workflow. 

2) For a GUI application - make a list of all GUI controls. For each control start writing test cases for testing of the control UI, functionality (impact on the whole application), negative testing (for incorrect inputs), performance etc.  

CURSOR STABILITY:

- CS is a row level locking

- Acquires an exclusive lock on the row that is to be updated

- When the control is moved to the next updatable row, the lock is released

REPEATABLE READ:

- RR is a page level locking

- Acquires an exclusive lock on the entire page which is the source of row availability

- When the control is moved to the next updatable page the lock is released