0
Database Design
Database design is the process of creating a detailed data model of a database. It is the next step after requirement gathering and before coding begins. A good database design can save a lot of time during the database development.
1,295 Questions
What is definition of a database system architecture?
The generalized architecture of a database system is called the ANSI/SPARC model.many commercial systems and research database models fit within this framework.It can be divided into the following three levels :
(a) External level or View level
(b) Conceptual level
(c) Internal level or Physical level
By Lubna Khan
This model helps you to get everything to work together. You can bring in little details and not worry about them getting lost.
1 Explain architecture of Distributed Database systems? Also, explain the reasons for building distributed database systems?
What is a primary key of one file that appears in another file?
A primary key is one that uniquely identifies a record . Also there are cases when primary key of one file appears in another file. In that case the key is called Foreign key.
Difference between the dynamic timing analysis and static timing analysis?
Dynamic timing analysis uses simulation vectors to verify that the circuit computes accurate results from a given input without any timing violations. The problem is that the simulations vector not can guarantee 100% coverage. The goal for the dynamic analysis is to get a 100% coverage. Dynamic timing simulation is still preferred for non-synchronous logic style. As a rule, however, only dynamic timing verification tools support glitch detection and race conditions, since these are inherently dynamic events. Static timing analysis on the other hand check all path in the circuit even the false paths. False paths are paths that are not possible or interesting in actual operation of the circuit. Therefore you can say that static analysis starts above 100% and works towards 100% by detecting and excluding the false paths. Static tools have made major advancements in recent years, in fact all synthesis tools use static timing analysis internally. Something good about this approach is that almost all tools using it supports multi-cycle paths, in which a path delay constraint exceeds a single clock period. Everything isn't just good, many static timing tools have problems with feedback loops. Problems with both approaches have resulted in the formation of a new tool categoryhybrid timing verification. It selectively combine both static and dynamic timing in an attempt to create the best of both worlds.
regards: VIPUL RAJPUT , Trident Techlabs Pvt. Ltd. Delhi
When were pencil cases first used?
back in the edwardian period when people were storing their quills and ink, they were more like quill bags rather than pencil cases.
Algorithm for finding binary representation of positive decimal integer?
I am assuming you mean positive integer in decimal notation.
Here is an algorithm that lists the binary representation backwards, that is
from right to left, least significant digit first.
N is the number decimal number
While N > 0
print N rem 2 // output the remainder
N = N/2 // replace N by n divided by 2
end loop
Example: trace for n = 101
n output
101
50 1
25 0
12 1
6 0
3 0
1 1 -- Last one had 0; 3%2 is 1
0 1
Output would be 1010011 ---- from left to right would be 1100101
Check: 64 + 32 + 0 + 0 + 4 + 1 = 101.
How Hierarchical Structure differs from Network Structure?
A network structure is more a star topology whereas a Hierarchical structure is like a tress... Allowing you to drill down to get to an answer.
Characteristics of data warehouse?
Hi,
1. Subject Oriented
2. Integrated
3. Nonvolatile
4. Time Variant
What characteristics could a database field have, such as data type, field name, field size and field format?
Relation means that someone has a familial connection. It can also mean that things are similar or connected to each other.
A database takes in information. Then it organizes it according to the user's specifications and saves it until it is needed. The database can be accessed by using a software program to retrieve information.
What are the causes for Ora-00904 invalid identifier while inserting in a table?
I don't have the Oracle docs to check for sure, but it sounds like you were trying to insert a value into a field that was invalid for that field definition. You cannot insert a character (CHAR) into a numeric (NUM) field. If it's a date field, then you can only insert a date into that field. Look at your insert statement--and compare it to the table definition--field by field. Also, you may be inserting more values than you have field defined. You can also make sure all of your "" are before and after each value.
What is the difference between table and form?
If you mean in a website, this is your answer.
A table is for the layout of the page and there you place images and text, a form is for entering information such as name, dates, addresses etc...
Hope this helped.
What is the best learning management system?
As per my knowledge VClassrooming is really good. It can be used by school, college or any other educational institute.
System that store data that is related to each other are known as database system. Example of database system : mysql, sql+, oracle etc.
Database programming language?
Depends upon the database you are talking about MS SQL Server uses SQL and T-SQL programming languages. Oracle is also a SQl based language usings its own 'flavor' PSQL
What are the Disadvantages of parallel database architecture?
Following are the disadvantages of parallel processing system.1) Number of resources required is large thus cost is increased.
2) Also due to large number of resources complexity is increased.
Example for relational data model?
here is a good website for that.
http://www.databaseanswers.org/data_models/index.htm
Describe the approach taken to handlin of data in the early file based system?
Focus was on applications for which programs would be written, and all the data required would be stored in a file or files owned by the programs.
Clearly, each program was responsible for only its own data, which could be repeated in other program's data files. Different programs could be written in different languages, and would not be able to access another program's files. This would be true even for those programs written in the same language, because a program needs to know the file structure before it can access it.
What are the advantages and disadvantages of bar codes?
There are two basic advantages to barcode over manual data entry: Speed, and Accuracy. For 12 characters of data, keyboard entry takes 6 seconds. Scanning a 12 character barcode takes .3 seconds. The error rate for typing is one substitution error in every 300 characters types. Error rated for barcode range from 1 substitution error in every 15,000 to 36 trillion characters scanned (depending on the type of barcode). A data entry error will translate into additional costs for a business which ranges from the cost of rekeying the data to shipping the wrong product to the wrong customer. Saving from these two advantages will usually pay for the cost of a barcode system in under two years. The only disadvantage is that data must be coded in the barcode. This can be an additional cost, however the key to an effective barcode system is to generate the barcode as close to the source of the data as possible. That means that the source of a product should be bar coding data that others in the supply chain will use.
speed and accuracy are advantages and the disadvantage is that w/out a description on the barcode you need a scanner or a computer to tell you what the product is
In database design what is a business rule?
Very good question!
A business rule is just as it states. Lets take a look at a really simple example first; Let say for example a business has a RULE that on its web site when you are filling out a form that the First Name field can only contain 20 characters, that's the rule!
In the database you would apply a constraint (some might do this at program level) that permits the First Name field to only contain 20 character.
Now business rules typically go MUCH deeper than that. Business rules in an application, or program simply represent constraints or processes that you put in place in order to comply with the rules set out by the business. These rules can be corporate rules or simply limitations, or constraints that yield the appropriat outcome as setup in the scope of work (The technical document that tells you what your program needs to do, how it is to look, how end users are to interact with it, ect).
If you need more detail please ask.
Jeff
