Welcome to Read: 08
SQL
In this Read: 08, I will talk about this topic:
- SQL.
SQL
What is SQL?
SQL, or Structured Query Language, is a language designed to allow both technical and non-technical users query, manipulate, and transform data from a relational database. And due to its simplicity, SQL databases provide safe and scalable storage for millions of websites and mobile applications.
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Relational databases
- Before learning the SQL syntax, it’s important to have a model for what a relational database actually is. A relational database represents a collection of related (two-dimensional) tables. Each of the tables are similar to an Excel spreadsheet, with a fixed number of named columns (the attributes or properties of the table) and any number of rows of data..
- Before learning the SQL syntax, it’s important to have a model for what a relational database actually is. A relational database represents a collection of related (two-dimensional) tables. Each of the tables are similar to an Excel spreadsheet, with a fixed number of named columns (the attributes or properties of the table) and any number of rows of data..
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What Can SQL do?
- SQL can execute queries against a database
- SQL can retrieve data from a database
- SQL can insert records in a database
- SQL can update records in a database
- SQL can delete records from a database
- SQL can create new databases
- SQL can retrieve data from a database
- SQL can create new tables in a database
- SQL can create stored procedures in a database
- SQL can create views in a database
- SQL can set permissions on tables, procedures, and views
- SQL can execute queries against a database
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How to Use SQL؟
- SQL Code Example:
SELECT * FROM Members WHERE Age > 30SQL syntaxes used in different databases are almost similar, though few RDBMS use a few different commands and even proprietary SQL syntaxes
- SQL Code Example:
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Types of SQL Statements
- Data Definition Language (DDL)
- Data Manipulation Language (DML)
- Data Control Language (DCL)
- Transaction Control Language (TCL)
- Data Query Language (DQL)
- Data Definition Language (DDL)
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List of SQL Commands
- CREATE - defines the database structure schema
- INSERT - inserts data into the row of a table
- UPDATE - updates data in a database
- DELETE - removes one or more rows from a table
- SELECT - selects the attribute based on the condition described by the WHERE clause
- DROP - removes tables and databases
- CREATE - defines the database structure schema
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| Read: 02 | jQuery, Events, and The DOM | |
| Read: 03 | Flexbox and Templating | |
| Read: 04 | Responsive Web Design and Regular Expressions | |
| Read: 05 | Heroku Deployment | |
| Read: 06 | Node, Express, and APIs | |
| Read: 07 | APIs continued | |
| Read: 08 | SQL | |
| Read: 09 | Refactoring | |
| Read: 10 | The Call Stack and Debugging | |
| Read: 11 | EJS | |
| Read: 12 | Components | |
| Read: 13 | Update/Delete | |
| Read: 14a | DB Normalization | |
| Read: 15 | Diversity and Inclusion | |