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Data definition language. Saving a ddl file in Oracle SQL Developer. In the context of SQL, data definition or data description language (DDL) is a syntax for creating and modifying database objects such as tables, indices, and users. DDL statements are similar to a computer programming language for defining data structures, especially database ...
A foreign key is a set of attributes in a table that refers to the primary key of another table, linking these two tables. In the context of relational databases, a foreign key is subject to an inclusion dependency constraint that the tuples consisting of the foreign key attributes in one relation, R, must also exist in some other (not necessarily distinct) relation, S; furthermore that those ...
Create, read, update and delete. In computer programming, create, read, update, and delete (CRUD) are the four basic operations of persistent storage. [1] CRUD is also sometimes used to describe user interface conventions that facilitate viewing, searching, and changing information using computer-based forms and reports.
SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce after learning about the relational model from Edgar F. Codd [12] in the early 1970s. [13] This version, initially called SEQUEL (Structured English Query Language), was designed to manipulate and retrieve data stored in IBM's original quasirelational database management system, System R, which a group at IBM San ...
Microsoft SQL Server (Structured Query Language) is a proprietary relational database management system developed by Microsoft.As a database server, it is a software product with the primary function of storing and retrieving data as requested by other software applications—which may run either on the same computer or on another computer across a network (including the Internet).
In computing, SQL injection is a code injection technique used to attack data-driven applications, in which malicious SQL statements are inserted into an entry field for execution (e.g. to dump the database contents to the attacker). [1][2] SQL injection must exploit a security vulnerability in an application's software, for example, when user ...
The Foreign Key serves as the link, and therefore the connection, between the two related tables in this sample database. In a relational database, a candidate key uniquely identifies each row of data values in a database table. A candidate key comprises a single column or a set of columns in a single database table. No two distinct rows or ...
It is the process of altering the original data file, allowing for the subsequent recovery of embedded auxiliary data referred to as a watermark. A subscriber, with knowledge of the watermark and how it is recovered, can determine (to a certain extent) whether significant changes have occurred within the data file.