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| + | ====== SQL ====== | ||
| + | <data programminglanguage> | ||
| + | Full Name: Structured Query Language | ||
| + | Short Name: SQL | ||
| + | Description: | ||
| + | Company: ISO/IEC | ||
| + | Web: No | ||
| + | Mobile: No | ||
| + | Enterprise: Yes | ||
| + | Embedded : Yes | ||
| + | </ | ||
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| + | SQL (Structured Query Language) is a standard programming language used to manage and manipulate data in relational databases. It is used to create, modify, and query databases, and is commonly used in web development, | ||
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| + | Some popular RDBMS that use SQL include MySQL, PostgreSQL, Oracle Database, Microsoft SQL Server, and SQLite. | ||
| + | </ | ||
| + | A database schema is a blueprint for a database that defines the structure of the tables, fields, and relationships within the database. It provides a framework for organizing and storing data, and is a fundamental concept in database design. | ||
| + | </ | ||
| + | A query in SQL is a request for data from a database. It is typically used to extract specific information from one or more tables, and can involve filtering, sorting, and joining data. | ||
| + | </ | ||
| + | A join in SQL is a method for combining data from two or more tables based on a common field or set of fields. There are several types of joins in SQL, including inner join, left join, right join, and full outer join. | ||
| + | </ | ||
| + | Normalization is the process of organizing data in a database to eliminate redundancy and reduce data inconsistencies. It involves breaking down a database into smaller, more manageable tables, and establishing relationships between the tables. | ||
| + | </ | ||
| + | An index in SQL is a data structure that improves the speed of data retrieval operations on a database. It is typically used to speed up queries that involve searching or sorting data, and can significantly improve database performance. | ||
| + | </ | ||
| + | A transaction in SQL is a sequence of database operations that must be completed as a single unit of work. Transactions ensure data consistency and integrity by guaranteeing that either all of the operations in the sequence are completed, or none of them are. Transactions are used to implement the ACID (atomicity, consistency, | ||
| + | </ | ||
| + | A stored procedure in SQL is a precompiled block of SQL code that is stored in a database and can be executed multiple times. Stored procedures are commonly used to encapsulate complex database operations, and can improve performance by reducing the amount of data that is sent between the database and the application. | ||
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| + | SQL injection is a type of security vulnerability that occurs when an attacker is able to inject malicious SQL code into a database query, either through a web application or other interface. SQL injection attacks can be used to extract sensitive data from a database, modify or delete data, or even gain full control of a database server. | ||
| + | </ | ||
| + | NoSQL (Not Only SQL) is a category of databases that do not use the traditional table-based relational database model of SQL databases. Instead, NoSQL databases use a variety of data models, such as key-value, document, or graph-based, | ||
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| + | {{wp> | ||
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| + | * https:// | ||
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| + | SQL stands for structured query language. It uses commands such as " | ||
| + | </ | ||
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| + | < | ||
| + | ===== Hello World ===== | ||
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| + | <sxh sql> | ||
| + | Declare @Output varchar(16) | ||
| + | Set @Output=' | ||
| + | Select ' | ||
| + | </ | ||
| + | <WRAP column right>< | ||
| + | </ | ||
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| + | See also: [[dev: | ||
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| + | {{tag> | ||