17acef57b4
chore: add pre-commit hooks chore: add pre-commit hooks chore: add pre-commit hooks chore: add pre-commit hooks
24 lines
1.3 KiB
Plaintext
24 lines
1.3 KiB
Plaintext
=== Data Definition Language (DDL)
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Data definition language includes commands for defining data structures. DDL commands are commonly used to define a database's schema. The schema refers to the overall structure or organization of the database and. in SQL databases, includes objects such as tables, indexes, views, relationships, triggers, and more.
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If an attacker successfully "injects" DDL type SQL commands into a database, he can violate the integrity (using ALTER and DROP statements) and availability (using DROP statements) of a system.
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* DDL commands are used for creating, modifying, and dropping the structure of database objects.
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* CREATE - create database objects such as tables and views
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* ALTER - alters the structure of the existing database
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* DROP - delete objects from the database
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* Example:
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** CREATE TABLE employees( +
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userid varchar(6) not null primary key, +
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first_name varchar(20), +
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last_name varchar(20), +
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department varchar(20), +
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salary varchar(10), +
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auth_tan varchar(6) +
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);
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** This statement creates the employees example table given on page 2.
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Now try to modify the schema by adding the column "phone" (varchar(20)) to the table "employees". :
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