What are the main phases of database?
- Conceptual design. When every data requirement is stored and analyzed, the next thing that we need to do is creating a conceptual database plan. ...
- Logical Design. The logical phase of database design is also called the data modeling mapping phase. ...
- Normalization. ...
- Physical Design.
This phase consists of three parts: the conceptual design, the logical design and the physical design. Some methodologies merge the logical design phase into the other two phases.
The five major components of a database are hardware, software, data, procedure, and database access language.
Schema is of three types: Logical Schema, Physical Schema and view Schema. Logical Schema – It describes the database designed at logical level. Physical Schema – It describes the database designed at physical level. View Schema – It defines the design of the database at the view level.
A database management system is a software tool that makes it possible to organize data in a database. It is often referred to by its acronym, DBMS. The functions of a DBMS include concurrency, security, backup and recovery, integrity and data descriptions.
These two stages are database planning stage and the database development stage. The first stage of the database design process is the database planning stage . The planning stage involve activities such as understanding the data requirements and creating data models.
The three levels present in this architecture are Physical level, Conceptual level and External level.
The first step is requirements gathering. During this step, the database designers have to interview the customers (database users) to understand the proposed system and obtain and document the data and functional requirements.
Database design is the organization of data according to a database model. The designer determines what data must be stored and how the data elements interrelate. With this information, they can begin to fit the data to the database model. Database management system manages the data accordingly.
MySQL, SQL Server, MongoDB, Oracle Database, PostgreSQL, Informix, Sybase, etc. are all examples of different databases. These modern databases are managed by DBMS.
What are the three 3 major categories of SQL?
SQL Commands can be grouped into following depending on their functionality: DDL (Data Definition Language) DML (Data Manipulation Language) TCL (Transaction Control Language)
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Mainly Constraints on the relational database are of 4 types:
- Domain constraints.
- Key constraints.
- Entity Integrity constraints.
- Referential integrity constraints.
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They are namely:
- Hierarchical databases.
- Network databases.
- Object-oriented databases.
- Relational databases.
- NoSQL databases.
- End Users.
- Application Programmers.
- Database Administrator.
There are three types of user-defined functions in SQL Server: Scalar Functions (Returns A Single Value) Inline Table Valued Functions (Contains a single TSQL statement and returns a Table Set) Multi-Statement Table Valued Functions (Contains multiple TSQL statements and returns Table Set)
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The other three include:
- hierarchical database systems.
- network database systems.
- object-oriented database systems.
What are basic design principles? There are twelve basic principles of design: contrast, balance, emphasis, proportion, hierarchy, repetition, rhythm, pattern, white space, movement, variety, and unity.
A database design helps data to be stored which is relevant and required. It is one important feature in database design. Consider a parent and a child record. The data present in child record is allowed if and only if the data is present in parent record.
Databases are widely divided into two major types or categories, namely, Relational or Sequence Databases and Non-relational or Non-sequence databases or No SQL databases.
Definition of Database or Database meaning: A database is a systematic collection of data. They support electronic storage and manipulation of data. Databases make data management easy. DBMS stands for Database Management System. We have four major types of DBMSs namely Hierarchical, Network, Relational, Object- ...
What are the 3 main clauses of a SQL statement?
- CONSTRAINT clause.
- FOR UPDATE clause.
- FROM clause.
- GROUP BY clause.
- HAVING clause.
- ORDER BY clause.
- The result offset and fetch first clauses.
- USING clause.
Commonly used DDL in SQL querying are CREATE, ALTER, DROP, and TRUNCATE.
DDL is Data Definition Language which is used to define data structures. For example: create table, alter table are instructions in SQL. DML: DML is Data Manipulation Language which is used to manipulate data itself. For example: insert, update, delete are instructions in SQL.
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Types of Integrity Constraint
- Domain constraints. ...
- Entity integrity constraints. ...
- Referential Integrity Constraints. ...
- Key constraints.
- Approach-1 : Self-Describing Nature of a Database System :
- Approach-2 : Isolation between Programs and Data, and Data Abstraction :
- Approach-3 : ...
- Approach-4 :
Datafiles, Redo log files and Control files are the mandatory components of a physical database structure. Datafile: This component stores the actual data. Each datafile is associated with only one database and tablespace.
A good database design is, therefore, one that: Divides your information into subject-based tables to reduce redundant data. Provides Access with the information it requires to join the information in the tables together as needed. Helps support and ensure the accuracy and integrity of your information.
Database systems are designed to meet a set of properties known as ACID. Atomicity, Consistency, Isolation, and Durability are the properties that constitute ACID.
Databases typically have one of two basic forms: single-file or flat file database. multi-file relational or structured database.
Types of database models
Relational model. Network model. Object-oriented database model. Entity-relationship model.
What are the 4 main objectives of a database?
Based on the Information Architecture Principle, every database can be architected or evaluated by six interdependent database objectives. Four of these objectives are primarily a function of design, development, and implementation: usability, extensibility, data integrity, and performance.
- Relational database.
- Object-oriented database.
- Hierarchical database.
- Network database.
- Short-term data. This is typically transactional data. ...
- Long-term data. One of the best examples of this type of data is certification or accreditation data. ...
- Useless data. Alas, too much of our databases are filled with truly useless data.
Importance of Database Design
To ensure data accuracy, you must design a database that only stores relevant and valuable information. A well-designed database is essential to guarantee information consistency, eliminate redundant data, efficiently execute queries, and improve the database's performance.
A good database design is, therefore, one that: Divides your information into subject-based tables to reduce redundant data. Provides Access with the information it requires to join the information in the tables together as needed. Helps support and ensure the accuracy and integrity of your information.
DBLC consists of five Stages
Logical Design. Physical Design. Implementation. Monitoring, Modification, and Maintenance.
The methodology is depicted as a bit by bit guide to the three main phases of database design, namely: conceptual, logical, and physical design.
The Database Life Cycle (DBLC) contains six phases, as shown in the following Figure: database initial study, database design, implementation and loading, testing and evaluation, operation, and maintenance and evolution.
- Hierarchical Data Model. A hierarchical data model is a structure for organizing data into a tree-like hierarchy, otherwise known as a parent-child relationship. ...
- Relational Data Model. ...
- Entity-relationship (ER) Data Model. ...
- Object-oriented Data Model. ...
- Dimensional Data Model.