DMLDDLDCL AND NORMALIZATION
DownloadTélécharger
Actions
Vote :
ScreenshotAperçu
Informations
Catégorie :Category: nCreator TI-Nspire
Auteur Author: SPITZER2001
Type : Classeur 3.0.1
Page(s) : 1
Taille Size: 2.44 Ko KB
Mis en ligne Uploaded: 20/11/2024 - 17:21:00
Uploadeur Uploader: SPITZER2001 (Profil)
Téléchargements Downloads: 8
Visibilité Visibility: Archive publique
Shortlink : https://tipla.net/a4329840
Type : Classeur 3.0.1
Page(s) : 1
Taille Size: 2.44 Ko KB
Mis en ligne Uploaded: 20/11/2024 - 17:21:00
Uploadeur Uploader: SPITZER2001 (Profil)
Téléchargements Downloads: 8
Visibilité Visibility: Archive publique
Shortlink : https://tipla.net/a4329840
Description
Fichier Nspire généré sur TI-Planet.org.
Compatible OS 3.0 et ultérieurs.
<<
DML, DDL, and DCL are categories of SQL commands used to interact with databases . Here's what they mean: 1. DDL (Data Definition Language) Purpose: Defines the structure of the database (e.g., tables, schemas). Key Operations: CREATE: Creates a new table, database, or schema. ALTER: Modifies the structure of an existing table (e.g., add/remove columns). DROP: Deletes a table, database, or schema permanently. TRUNCATE: Removes all records from a table (faster than DELETE but cannot be rolled back). RENAME: Renames a table or object. 2. DML (Data Manipulation Language) Purpose: Used to manipulate and retrieve data from the database. Key Operations: SELECT: Retrieves data from the database. INSERT: Adds new records to a table. UPDATE: Modifies existing records in a table. DELETE: Removes records from a table. 3. DCL (Data Control Language) Purpose: Manages permissions and access to the database. Key Operations: GRANT: Gives a user permission to perform specific actions (e.g., SELECT, INSERT). REVOKE: Removes permissions from a user. Normalization is a process used in database design to organize data efficiently. The goal is to reduce redundancy (repeated data) and avoid inconsistencies by breaking down a database into smaller, related tables. This ensures data integrity and makes databases easier to maintain. Normalization is performed in stages, called Normal Forms (NFs). Each stage solves specific issues. The Normal Forms First Normal Form (1NF): Ensures each column contains only atomic values (single, indivisible values). Removes repeating groups or arrays in a table. A unique identifier (primary key) is required to identify rows. Second Normal Form (2NF): The table must already be in 1NF. Removes partial dependency, meaning all non-key attributes should depend on the entire primary key (not just part of it). Third Normal Form (3NF): The table must be in 2NF. Removes transitive dependency, where non-key attributes depend on other non-key attributes instead of the primary key. Why Normalize? Reduce redundancy: Avoid storing the same data multiple times. Improve data consistency: Make it easier to update data without errors. Ensure data integrity: Avoid conflicting or incorrect data. Made with nCreator - tiplanet.org
>>
Compatible OS 3.0 et ultérieurs.
<<
DML, DDL, and DCL are categories of SQL commands used to interact with databases . Here's what they mean: 1. DDL (Data Definition Language) Purpose: Defines the structure of the database (e.g., tables, schemas). Key Operations: CREATE: Creates a new table, database, or schema. ALTER: Modifies the structure of an existing table (e.g., add/remove columns). DROP: Deletes a table, database, or schema permanently. TRUNCATE: Removes all records from a table (faster than DELETE but cannot be rolled back). RENAME: Renames a table or object. 2. DML (Data Manipulation Language) Purpose: Used to manipulate and retrieve data from the database. Key Operations: SELECT: Retrieves data from the database. INSERT: Adds new records to a table. UPDATE: Modifies existing records in a table. DELETE: Removes records from a table. 3. DCL (Data Control Language) Purpose: Manages permissions and access to the database. Key Operations: GRANT: Gives a user permission to perform specific actions (e.g., SELECT, INSERT). REVOKE: Removes permissions from a user. Normalization is a process used in database design to organize data efficiently. The goal is to reduce redundancy (repeated data) and avoid inconsistencies by breaking down a database into smaller, related tables. This ensures data integrity and makes databases easier to maintain. Normalization is performed in stages, called Normal Forms (NFs). Each stage solves specific issues. The Normal Forms First Normal Form (1NF): Ensures each column contains only atomic values (single, indivisible values). Removes repeating groups or arrays in a table. A unique identifier (primary key) is required to identify rows. Second Normal Form (2NF): The table must already be in 1NF. Removes partial dependency, meaning all non-key attributes should depend on the entire primary key (not just part of it). Third Normal Form (3NF): The table must be in 2NF. Removes transitive dependency, where non-key attributes depend on other non-key attributes instead of the primary key. Why Normalize? Reduce redundancy: Avoid storing the same data multiple times. Improve data consistency: Make it easier to update data without errors. Ensure data integrity: Avoid conflicting or incorrect data. Made with nCreator - tiplanet.org
>>
