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it contains of cammands to create the object such as view,index etc
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∙ 11y ago
DDL (Data Definition Language) commands in SQL are used to define the structure of database objects. Some common DDL commands include:
- CREATE: Used to create database objects like tables, views, indexes, etc.
- ALTER: Used to modify the structure of existing database objects.
- DROP: Used to delete database objects.
- TRUNCATE: Used to delete all records from a table.
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What is an unsafe query and Give an example and explain why it is important to disallow such queries?
An unsafe query is a query that is vulnerable to SQL injection, allowing malicious users to run unauthorized commands on a database. Example: "SELECT * FROM users WHERE username = 'admin' AND password = 'password' OR 1=1;". It's crucial to disallow such queries to prevent security breaches, data manipulation, unauthorized access to information, and potential damage to the database.
What is the function of an SQL Loader?
SQL Loader is a utility used to load data from external files into an Oracle database. It can handle loading large volumes of data quickly and efficiently, and provides flexibility in mapping data from files to database tables. It is commonly used for bulk data loading tasks.
What SQL clause is used to restrict the rows returned by a query?
The WHERE clause is used to restrict the rows returned by a query in SQL. It allows you to specify a condition that must be met for a row to be included in the result set.
What is the function of a Foreign Key in SQL?
A Foreign Key in SQL is used to establish a relationship between two tables. It ensures referential integrity by enforcing that values in a column (or columns) in one table must match the values in a primary key in another table. This helps maintain consistency and data integrity across linked tables.
What is an unsafe query Give an example and explain why it is important to disallow such queries?
A query in which the output is possibly infinite. This most often occurs in queries which are recursive or which contain negation. Such queries are disallowed by many database management systems to prevent unsafe queries.
What is ddl interpert?
There are number of commands in database (SQL) that are used to control , manipulate , retrieve data. One such command is DDL which is used for defining the schema of database.
What are the sql commands with dml and ddl?
The DDL provides statement for the creation and deletion of tables, indexes, views etc. The DML provides statements to enter, update, delete and perform complex queries on these tables.
What is interperting?
There are number of commands in database (SQL) that are used to control , manipulate , retrieve data. One such command is DDL which is used for defining the schema of database.
What is the name of two DDL operations in SQL?
Some of the operations performed in DDL in sql are creation of table,alteration of table,truncate a table, drop a table
Explain the DDL and DML commands in sql with example?
DDL--Data Definition Languageand Commands for DDL as:1.CREATE DATABASE--create a new data base2.ALTER DATABASE---modifies a database3.CREATE TABLE---create a new table4.ALTER TABLE---modifies a table5.DROP TABLE---deletes a table6.CREATE INDEX---creates an index(search key)7.DROP INDEX---deletes an indexDML---Data Manipulation LanguageCommands from the DML part of SQL:1.SELECT----extracts data from a database2.UPDATE--updates data in a database3.DELETE---deletes data from a database4.INSERT INTO---insert new data into a database
Difference between alter and update commands in sql?
Update and Alter are two SQL (Structured Query Language) commands used for modifying databases. Update statement is used to update existing records in a database. Update is a Data Manipulation Language (DML) statement. Alter SQL command is used to modify, delete or add a column to an existing table in a database. Alter is a Data Definition Language (DDL) statement.Commands that are used to define the structure of a database (database schema) are called DDL statements.
How does SQL allow implementation of the entity integrity and referencial integrity constraints what about general integrity constraints?
sql allow their implementation using various sql commands
SQL statements that define the tables in a database are referred to as?
DDL Statments
What are the three update commands in sql?
The three update commands in SQL are SET, WHERE, AND FROM.
SQL is what language?
SQL stands for Structured Query Language. It is a programming language used to deal with relational databases. One can use SQL to view and manage databases. SQL is a domain-specific language, meaning it has a higher level of abstraction optimized for a specific class of problems. SQL commands can store, remove, update, and retrieve data from relational databases. SQL helps manage the data kept in databases and enables users to access the required data when needed. It is a simple but powerful programming language. In addition to deleting, updating, and extracting data, it can modify the database structures using SQL commands. The following are categories for SQL statements. DDL(Data definition language) Commands: The user can create and modify database objects using DDL based on their needs. So, the SQL commands used to create the database structure are known as data description language (DDL). Examples of DDL commands are CREATE, DROP, RENAME, and ALTER. DML(Data manipulation language) Commands: One can update their databases using the DML commands. One can insert a new record or delete an old record using the insert and delete commands, respectively. Examples of DML commands are INSERT, UPDATE, DELETE etc. DCL(Data control language) Commands: This command is generally used by database administrators to regulate or grant other users access to databases. For example, they can allow possible uses to modify one or more tables by using the GRANT command. Examples of DCL commands are GRANT and REVOKE. DQL( Data query language) Commands: These commands are used to access the relational databases. For example, a user can use the SELECT command to select and return detailed data from a SQL table. TCL(Transaction control language) Commands: TCL commands help the user in controlling transactions related to database operations. Examples of TCL commands are COMMIT and ROLLBACK. Some of the advantages of SQL language are as follows: It can provide users with a quick and efficient way to receive, modify, or store data resulting and efficient and fast query processing. Because it provides simple commands for all reasons, it becomes an interactive language for its users. Non-programmers can also grasp SQL commands. Because SQL primarily comprises English statements, it is easy to understand and create SQL queries. Without writing a lot of code, database systems are simple to manage. SQL is a portable language. Independent of any device, it can be used in software on PCs, servers, and laptops. Additionally, it can be integrated with other applications based on use, necessity, and need. SQL is easy to learn. Additionally, one can use it to connect to databases and instantly get solutions to challenging queries. The SQL language offers each user a different point of view on the data. It can be constructed from one or more tables depending on the written queries or the view's purpose. ANSI and ISO have approved the relational database query language SQL. As a result of appropriate documentation and years of establishment, it provides all users with a consistent platform globally.
What is DDL in databases?
DDL stands for Data Definition Language, which is a set of commands used to define, alter, and drop database objects like tables, indexes, and views. DDL statements include commands like CREATE, ALTER, and DROP, and they are used to design the structure of the database and its schema.
What was added to the most recent sql standard?
The most recent SQL standard came out late 2011. DDL features are one thing introduced into the newest SQL. It is used to improve the usability of generated and identity columns.
