Example:

Attributes | First Name | Last Name | Age | Sex |
---|---|---|---|---|

Values | Elliyas | Ahmed | 24 | Male |

**Data Item:**Single unit of values.**Sub Items:**Here First Name and Last Name are two Sub Items.**Group Items:**Color = {Red, Blue, Violet}

**Elements of organized data:** Fields, Records, Files.

**Field:**A single elementary unit to represent an attribute of an entity. Example: Age, Sex**Record**: A collection of field.**File**: A collection of record.

**Primary Key:** An attribute from a record can serve as Primary key if it be the unique. Observe the following record:

SL. NO | Student Name | Session | Age |
---|---|---|---|

1 | Masud Parvej | 2012-2013 | 24 |

2 | Rahul Roy | 2009-2010 | 27 |

3 | Masud Parvej | 2013-2014 | 24 |

Here *SL.NO* attribute is the unique. Because, the values of other attributes (*Student Name, Session, Age*) may be same but the values of first attribute can’t be same. So *SL.NO* is the primary key for this record.

**Data Structure:** The organization of Data in logical or mathematical is called Data Structure.

**Arrays:**Type of Data Structure that contains a list of finite numbers or characters.**Linked Lists:**Linked list is a linear collection of elements (of data) and the order of linear is ordered by means of pointer.**Trees:**A non linear data structure to represent the relationship between element in hierarchical.**Stack:**Stack is a list of elements, in which element can be inserted or deleted from the top. So it is known as LIFO (Last In First Out). Example: Stacks of plates in a bucket.**Queue:**Queue is a list of elements, in which element can be deleted from the bottom or end. So it is known as FIFO (First In First Out). Example: A Queue of Bus.**Graph:**A graph is a non linear data structure which is consist of nodes and edges.

**Data Structure Operations:**

**Traversing:**Accessing all record exactly once sequence by sequence. Example: Reading, Printing all the elements of a record once.**Searching:**Finding the location of a given value from record base on condition.**Inserting:**Adding new record to the given record.**Deleting:**Removing any record from the given record. Sorting: Arranging records in logical or mathematical order.**Merging:**Appending records.

**Algorithms**

**Algorithm:** he easiest and effective steps for solving a problem. Complexity: It is the function of algorithm that returns running time, memory space in terms of input. Questions on this lesson:

Try to solve without revise. If you can’t, try again from the beginning of this lesson.

- What is the main difference between field, record, file?
- For a record, what is the condition for an attribute to serve as primary key?
- What are the major operations of Data Structure? What is the measure of complexity of algorithm?