Evolution and Properties of Relational Database Models
Evolution of Relational Database Systems (1980-1990)
- Development of large relational systems – SQL commercial.
- Development of application generators.
- Distributed systems.
- Client/server structure (visual languages).
- Object-oriented relational model.
New Data Representation Models (1980-1990)
- Problems in the relational model: The semantics of complex items are poorly reflected.
- Connection of existing data with information in the DB.
- “Intelligent” unified representation of rules and data, knowledge bases, intelligent
Microprocessor Bus and Memory Types: Essential Functions
What is the Role of the Address Bus?
The address bus is a totally independent channel from the microprocessor to the data bus, which contains the memory address of the data in transit. It consists of a set of power lines needed to establish a directional memory capacity. The addressable memory capacity depends on the number of bits that make up the address bus, with 2n (two raised to the n) representing the maximum bytes of the memory bank that can be addressed using *n* lines.
What Does the Data
Read MoreUnderstanding JK Flip-Flops: Race Condition & Master-Slave Design
Understanding Race Conditions and Master-Slave JK Flip-Flops
The JK flip-flop diagram below represents the basic structure, which consists of Clock (CLK), Clear (CLR), and Preset (PR).
Race Around Condition in JK Flip-Flops
For a JK flip-flop, if J=K=1, and if clk=1 for a long period, the output Q will toggle as long as CLK remains high, making the output unstable or uncertain.
This is called a race around condition in a JK flip-flop.
We can overcome this problem by ensuring the clock =1 for a very short
Read MoreUnderstanding Gray Code, DVD-RW, HSDPA, and User Access
Understanding Key Digital Concepts
Gray Code (Reflected Binary Code)
The reflected binary code, or Gray code, named after researcher Frank Gray, is a binary numeral system where two successive values differ in only one digit. The Gray code was originally designed to prevent spurious signals from electromechanical switches. It is currently used to facilitate error correction in communication systems, such as certain cable television systems and digital terrestrial television.
A code is called Johnson
Read MoreDatabase Management Systems: Concepts and Applications
A database management system (DBMS) is a software package designed to define, manipulate, retrieve, and manage data in a database.
Characteristics of DBMS
- Provides security and removes redundancy (duplication)
- Insulation between programs and data abstraction
- Support of multiple views of the data
- Sharing of data and multiuser transaction processing
- DBMS allows entities and relations among them to form tables.
Objective of DBMS
- Eliminate redundant data.
- Make access to the data easy for the user.
- Provide for
Understanding Office Automation: Components and Configuration
Understanding Office Automation
Phases of Company Information Management: Collection, storage, processing, distribution, and presentation.
Office Automation: The branch of computer science focused on automating typical office processes.
Key Components of Office Automation
Word Processor: Enables creating, manipulating, and storing text with various formatting options and automatic spell checking.
Spreadsheet: Allows entering text and numbers for automatic calculations and presenting results in different
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