Database Programming

Foreign keys isnt drawn at a ER-diagram. The relation drawn between entities is enough to show, that der is at foreign key

SELECT Warehouse, AVG(QuantityOnHand) AS QuantityOnHand

FROM INVENTORY

WHERE Warehouse

IN (SELECT Warehouse

FROM WAREHOUSE

WHERE Manager = 'Smith')

GROUP BY Warehouse;

110

QBE stands for Query by Example.

Computer programming

you disable it so that the flying ears or the Flashing camera will not work anymore.

A primary key is one or more colums in a table whose values would uniquely identify a row in that table.

A foreign key is a one or more columns in one table that are used to reference rows in another table. In a properly designed 3NF schema, the foreign key columns should correspond to the primary key columns of the table being referenced.

True

2500 MB (manufacturer standards), or 2560 MB (programming standards).

a functionaly dependency is an association between two relational attribute of same relational database.one of the attribute is known as determinant and the other one is determined.for the each value of determinant there is only one value associated of determined.

graphicaly it can be represented A----->B .

data can be define as stored representation,s of objects and events that have meaning and in important in the user,s environment. This definition include structured and unstructured datatype. Today structured and unstructured data are often combine in same database to created a true multimedia environment .

they are people who interact with a database system in different ways

and they are as follow

1- end users

2-database designers

3- database administrators

4- application programmers

Memory should be taken into account when building a database and maintain integrity and avoid redundancy through normalization.

• A description of the data structure that will store the end-user data.
• A set of enforceable rules to guarantee the integrity of the data.

# include < stdio.h >

# include < stdlib.h >

struct list

{

char info[20];

struct list *next;

struct list *prev;

};

struct list *new1,*node;

void create(struct list *s,struct list *e)

{

char ch;

node=s;

printf("\nWant to create a node(y/n):");

ch=getche();

while (ch != 'n')

{

node->next = (struct list *) malloc(sizeof(struct list));

node->next->prev= node;

node = node->next;

printf("\n Enter the string value:- ");

gets(node->info);

node->next = e;

e->prev=node;

printf("\n Enter choice--'n' for break: ");

ch = getche();

}

}

void displayL (struct list *s,struct list *e)

{

node = s->next;

while (node!=e)

{

printf(" 0x%x--%s", node,node->info);

node = node->next;

}

printf("\n");

}

void displayR (struct list *e,struct list *s)

{

node = e->prev;

while (node!=s)

{

printf(" 0x%x--%s", node,node->info);

node = node->prev;

}

printf("\n");

}

void insertA(struct list *s)

{

struct list *new1;

int c=1,count;

printf("\nEnter the location:");

scanf("%d",&count);

fflush(stdin);

new1 = (struct list *) malloc(sizeof(struct list));

printf("\nEnter the new value:");

gets(new1->info);

node=s->next;

while(node)

{

if(c==count)

break;

node=node->next;

c++;

}

node->prev->next=new1;

new1->prev=node->prev;

new1->next=node;

node->prev=new1;

}

void main()

{

struct list *start,*end;

clrscr();

start=(struct list *) malloc(sizeof(struct list));

end=(struct list *) malloc(sizeof(struct list));

create(start,end);

printf("\n Created list is as follows(L ->R)\n");

displayL(start,end);

printf("\n Created list displayed from R->L\n");

displayR(end,start);

printf("\nInserting a new location at user specified location\n");

insertA(start);

printf("\n now the listfrom L ->R\n");

displayL(start,end);

printf("\n list from R to L after insertion\n");

displayR(end,start);

getch();

}

what is responsibities of data processing officer

A loosely coupled system offers advantages such as increased flexibility and scalability, allowing components to be modified or replaced independently without affecting the entire system. This modularity can enhance resilience, as the failure of one component is less likely to disrupt others. However, disadvantages include potential performance overhead due to the need for communication between loosely connected components, and the complexity of managing interactions and dependencies, which can lead to challenges in system integration and consistency.

VSAM files are used when we want to store data based on some key fields(Eg: KSDS)

access method is indexed.

NON VSAM files like PS are used when we want to store data which is not unique and also the access is sequential.

possible

dbms is data base management system .It is combination of the data base & the the softwares to access the data from the database.

eg:Poracle 91,dbase;

for more reply to rexrer234@gmail.com

It must be enclosed in square brackets so that Access knows the words are associated with one entity. As a general rule, it is a good idea to use single words or multiple words with no spaces or an underscore between them, as these are easier to work with. Otherwise the application does not know if the word refer to one or more things and so you get errors.

Electronic Storage is usually referring to data stored on some type of computer related storage medium, such as hard drives, CDROM, memory cards, etc. In other words, its data in computer form, 1's and 0's, stored in a format that a computer understands.

Hard Copy storage would be on paper or the equivalent, stored in human form and readable by us.

A number of extensions to the relational data model have been proposed in the

three decades or so since its invention. Many of these extensions have been

implemented in commercial DBMS. What is termed the post-relational data

model here is not strictly a data model in that no coherent theory has been

developed. Nevertheless it is useful to discuss it here in terms of a set of mech-

anisms found in many contemporary DBMS. Such a data model is also referred

to by the terms extended-relational and object-relational data model. In

Chapter 18 we discuss how the proposed SQL3 standard addresses many of

these features. In Chapter 34 we also consider how the ORACLE DBMS

supports some of these features.

In the first half of the chapter we consider two extensions to the data defin-

ition part of the relational data model: abstract data types and nested relations.

In the second half of the chapter we consider two constructs - triggers and

stored procedures - that have been used both for data manipulation and data

integrity purposes. The incorporation of these features into a relational DBMS

provides it with the ability to handle complex objects and behaviour. Hence

many of the DBMS with these features have termed themselves object-rela-

tional systems.