Basic Terminologies
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Let us guide you through the Basic Terminologies that is necessary to know and will be used in the topics following this.
Table:
Table is a collection of rows and columns forming the combined data storage element. Every data is stored in a table and in addition, denotes the overall relationship with each other.
Tuple/Row:
A tuple is a specific row in the Table. It contains the information of records, that are filled by the User.
Attribute/Column:
An attribute is a specific column in the Database that defines the type of data that is to be filled by the user. Constraints can be added to the attributes to fix some limits to the data entry.
Query:
It is a complete syntactically correct statement that provokes a search over rows and columns, finding data that follows the specific condition given by the user. It may or may not include a computation involved for the process.
Primary Key:
It is a special Attribute in the Database that can be used to uniquely identify a particular Tuple out of the whole Table. A primary key can’t be duplicated or left empty. E.g.- Roll number, Product ID, etc.
Foreign Key:
It is very closely related to the Primary key. A foreign key is a primary key of another table that can be used to identify the tuples uniquely.
Data Redundancy:
It is a condition where the same data is stored at multiple places resulting in data and memory wastage. SQL helps to reduce that greatly.
Metadata:
It is information that depicts other information. Meta is a prefix that in most data innovation uses signifies “a hidden definition or depiction.” Metadata condenses fundamental data about information, which can make finding and working with specific examples of information simpler.
DDL:
It alludes to “Data Definition Language”, a subset of SQL articulations that change the structure of the database diagram here and there, normally by making, erasing, or altering pattern questions, for example, databases, tables, and perspectives.
DCL:
Data Control Language is utilized to control benefits in Database. To play out any task in the database, for example, for making tables, arrangements or perspectives a client needs benefits.
DML:
It refers to Data Manipulation Language. It is used to modify and create the structure of the database with its syntax elements.
TCL:
Stands for Transmission Control language. TCL directions are utilized to oversee exchanges in the database. These are utilized to deal with the progressions made to the information in a table by DML articulations. It likewise enables explanations to be gathered together into sensible exchanges.
