Database Programming

The 'null'-content of any given field is just that. It's a 'nothing'. Example, if you create a database to hold chemical values for instance. If the values are, for example, real nubers. That would imply that any value that has 0 in it, is just that; zero. It was beeing measured, and found to contain zero. On the other hand if a value was not tested, the value of that compound should be set to 'null'. If a 'null' value isn't supported by the database a workaround is to set 'null' values to -1 (as per the example above). --

Full form of OLEDB is Object Linking and Embedding database.

DFD diagram of company payroll system.

SQL

These are the main categories are

DDL(Data Definition Language)

DML ( Data Manipulation Language)

DQL( Data Query Language)

DCL( Data control Language)

Data administration commands

Transactional control command.

ddl includes insert ,delete ,update values

it include select statements,

it include insert statement,

it includes drop statements

So that the information can be managed easily, and retrieval, storage and modification can be done easily and in a faster way .

The redundancy can also be reduced ........

LIFO stands for Last In First Out.

Ex: Stack

Use this code:

#include <iostream>

using namespace std;

int main()

{int x;

for(x=0; x<27; x++)

if(x 26) cout<< "z" << endl;

return (0);

}

Transversing

Accessing each record exactly once so that certain items in the record may be processed.(This accessing or processing is sometimes called 'visiting" the records.)

Searching

Finding the location of the record with a given key value, or finding the locations of all records, which satisfy one or more conditions.

Inserting

Adding new records to the structure.

Deleting

Removing a record from the structure.

Sometimes two or more data structure of operations may be used in a given situation; e.g., we may want to delete the record with a given key, which may mean we first need to search for the location of the record.

The basic idea (you write functions CountChildren, GetChild, NewBinTree):

struct GenTree;

struct BinTree;

typedef struct GenTree GenTree;

typedef struct BinTree BinTree;

int CountChildren (const GenTree *from);

int GetChild (const GenTree *from, int which);

BinTree *NewBinTree (DATATYPE data, BinTree *left, BinTree *right);

BinTree *Convert (const GenTree *from)

{

BinTree *bt, *tmp;

int i, n;

if (from==NULL) return NULL;

n = CountChildren (from);

bt = NewBinTree (from->data, NULL, NULL);

if (n 1) return bt;

tmp = Convert (GetChild (from, n));

for (i=n-1; i<=2; --i) {

tmp= NewBinTree (<NODATA>, Convert (GetChild (from, i)), tmp);

}

bt->right = tmp;

return bt;

}

Active file: An active file is where you use a file quite frequently.

Inactive file: A file that you use but not as frequently.

Dead file: A dead file is where you don't use the file at all and is stored in your archives

A data record is a collection of various fields of data (like name, organisation, sex, age etc), whereas a database is a collection of records tables. (And views, indexes, stored procedures, and other stuff;)

Prototypes are normally built in a similar way to the final product however parts may differ slightly as they aren't always produced on a production line they are one off's made by hand or 'compatible' parts may be used instead to lower the cost of prototyping as it is a very expensive process.

Rapid prototyping uses 3D printing technologies to make prototype parts, this process also allows for no assembly of parts as they can be printed in place thus further speeding up the prototyping process. In some cases the material used isn't final but the process takes only hours compared to traditional weeks-months and can be used to test the fitting, visual appeal and dimensional properties of the product wanting to be prototypes.

In some cases computer modelling is used to make a prototype as you can test a design without ever having to build it physically. This has its draw backs of requiring large amounts of computing power and the models may require refinement to accurately reflect real scenarios.

the point of input voltage at which Q1 begins to conduct

Computers do not understand decimal notation. All information (both instructions and data) must be converted to a binary representation before the machine can understand it. We use the symbols 0 and 1 (binary notation) but the machine has a variety of physical representations it can use to encode binary data, including transistors, flux transitions, on/off switches and so on.

In software, an encoder takes some data and transforms it into a format suitable for storage or transmission.

In hardware, an encoder which takes multiple input lines and outputs the binary representation of the single input line which is set to high. Since it is difficult to guarantee that only a single input line will be high at the same time, a priority encoder is generally used instead.

Two method of representing a binary tree is

Static allocation, and

Dynamic allocation

there are certain rules to make up a relational data base management system, oracle follows it and so its an rdbms

Queue is better than stack because jobs in a queue are processed on a first in first out order thereby reducing traffic and delay.

But jobs in a stack are processed in a last in first out order causing traffic and delay of jobs that arrived earlier

The queue insert operation is known is enqueue.

A queue has two ends namely REAR & FRONT. After the data has been inserted in a queue ,the new element becomes REAR.The queue deletion operation is known as dequeue.

The data at the front of the queue is removed .

All data types can be used to store a whole number, even the data types that can store a decimal number.

1. Hide changes in the database hardware from the application
2. retrieval (query and reporting)
3. Security, integrity, backup, fault tolerance etc
4. DB Definition
5. DB revision and restructuring

less damages since it's done once in a financial year