SQL Reference - DATABASE

DATABASE

DATABASE in SQL is a structured set of data. In other words, it is the main container that holds data in an organized way for storing, managing, and retrieval. A DATABASE in SQL consists of series of tables that store specific sets of information. It takes a major role in the functioning of an application by allowing the storage, update, and retrieval of data. A DATABASE follows the ACID principles (Atomicity, Consistency, Isolation, Durability) to ensure reliability.

Example

CREATE DATABASE MyDatabase;
USE MyDatabase;
CREATE TABLE MyTable(ID int, Name varchar(255));
INSERT INTO MyTable VALUES (1, 'Name1');
SELECT * FROM MyTable;

Output

+----+-------+
| ID | Name  |
+----+-------+
|  1 | Name1 |
+----+-------+

Explanation

The example demonstrates the procedure of creating a database, using that database, and creating a table inside the database in MySQL. An entry is also inserted into the table and then the contents of the table are displayed.

Example

CREATE DATABASE test_db;

\c test_db;

CREATE TABLE test_table(
    ID INT PRIMARY KEY NOT NULL,
    NAME TEXT NOT NULL
);

INSERT INTO test_table (ID, NAME) VALUES (1, 'John');

SELECT * FROM test_table;

Output

 id | name
----+------
  1 | John
(1 row)

Explanation

In the example, first, a new database test_db is created. Then, a connection is established to the new database. Next, a new table test_table with columns ID and NAME is created in the test_db database. Afterwards, an entry, where ID is 1 and NAME is 'John', is inserted into test_table. Finally, using the SELECT statement, all records from test_table are retrieved, which currently only holds one entry. As a result, the output shows that single row with ID equalling 1 and NAME equalling 'John'.

Example

CREATE DATABASE TestDB;

Output

-- Command(s) completed successfully.

Explanation

The above SQL code snippet creates a new database named TestDB. When executed successfully, the SQL Server returns a message stating that the command(s) completed successfully.

Example

CREATE DATABASE sampleDB;

Output

Database created.

Explanation

In Oracle SQL, the CREATE DATABASE statement is used to create a new database. In this case, a database named sampleDB has been created.

Example

CREATE DATABASE example_db;

Output

Query OK, 1 row affected (0.00 sec)

Explanation

In this example, a command CREATE DATABASE is used to create a new database called ‘example_db’. The command creates an entirely new database and an output message “Query OK, 1 row affected” confirms that the command executed successfully and a new database has been created.