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Definition
| An organized collection of logically related data/information to provide effecient retrieval |
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Term
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Definition
Software that handles the storage, retrieval and updating of data in a computer system
–E.g. Perl, Python, MySQL |
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Definition
| Relational Database Management System |
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Term
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Definition
Software that handles the storage, retrieval and updating of data in a computer system based on relational model
–E.g. Microsoft SQL Server, Oracle, Access, DB2 |
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Term
| realational model consist of |
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Definition
Collection of objects or relations
–Set of operators to act on the relations
–Data integrity for accuracy and consistency |
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Term
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Definition
| Dr. E. F. Codd proposed the relational model for database systems in 1970. |
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| Relational Database Terminology |
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Definition
| A relational database is a collection of relations ortwo-dimensional tables |
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Definition
| A two-dimensional structure made up of rows and columns |
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Definition
Represents all data required for an entity
–Each row is unique and stores data about an entity
–Also called as tuple or record
–Row order is unimportant |
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Definition
Represents characteristic of an entity
–Each column has a unique name
–Also called as attributes or fields
–Column order is unimportant
–Each column has a datatype
–All entries in a column has same datatype |
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Term
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Definition
An attribute or collection of attributes whose value(s) uniquely identify each row in a relation
–Must contain a value and the value must be unique
–A table can have only one primary key
–Can be made up of several fields (called
concatenated key or composite key) |
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Term
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Definition
An attribute or collection of attributes that defines how tables relate to each other
–Refers to a primary key in another table
–Data in this field must exactly match data contained
in a primary key field
Database
server
Table |
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Term
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Definition
A data structure that improves the speed of data retrieval operation on database table
–Created on a column of a table
–Types:
—Clustered
—Non-Clustered |
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Term
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Definition
Rules that restrict values in a database table
–Can be declared at column level or table level
–Types:
—Primary key constraint
—Unique constraint
—Foreign key constraint
—Check constraint |
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Term
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Definition
The process of efficiently organizing data to achieve the following goals:
—Avoid data redundancy
—Ensure data integrity
The process usually involves:
—breaking down a single table into two or more tables and
—defining relationships between those tables |
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Term
| Entity Relationship Diagram |
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Definition
A graphical representation of the data layout of a system at a high level of abstraction
•Defines:
–data elements
–their inter relationships in the system |
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Term
| Notation three main constructs |
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Definition
–Data Entities
–Relationships
–Attributes |
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Definition
| A collection of persons/ places/ objects/ events/ concepts in the real world for which data is collected and maintained |
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Definition
Persons: Employee, Student, Patient
–Places: Store, Warehouse
–Objects: Machine, Product, Car
–Events: Sale, Registration, Renewal
–Concepts: Account, Course |
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Definition
A property or characteristic that explains an entity
Employee: Emp_ID, Emp_Name, Emp_Address
–Registration: Reg_ID, Reg_Date
–Account: Acc_Number, Acc_Type |
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Definition
| An association or interaction between entities |
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Definition
Mandatory Relationship
—Optional Relationship |
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Term
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Definition
One-to-One Relationship
—One-to-Many Relationship
—Many-to-Many Relationship |
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Term
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Definition
| In a company, each division is managed by only one manager and each manager manages only one division |
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Definition
| Among the mobile manufacturing companies, a company manufactures many cars, but a given car is manufactured in only one company |
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| Many to many relationship |
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Definition
| In a college, every student takes as many courses and every course is taken by many students |
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Term
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Definition
| SQL statements are used to retrieve and update data in a database |
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Term
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Definition
Includes:
–Data Definition Language (DDL)
–Data Manipulation Language (DML) |
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Term
| DDL(Data Definition Language) |
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Definition
Syntax for creating ,editing, deleting:
–Databases
–Tables
–Views
–Indexes
–Constraints
–Users
–Privileges |
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Term
| DML (Data Manipulation Language) |
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Definition
Syntax for executing queries, updating, inserting, and deleting records.
–SELECT -extracts data from one or more table
–INSERT INTO -inserts new data into a table
–UPDATE -updates data in a table
–DELETE FROM -deletes data from a table |
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