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SQL CREATE DATABASE Statement
SQL DROP DATABASE Statement
SQL BACKUP DATABASE Statement
SQL CREATE TABLE Statement
The SQL DROP TABLE Statement The DROP TABLE statement is used to permanently delete an existing table in a database. Note: Be careful before dropping a table! Dropping a table deletes the entire tabl…
SQL ALTER TABLE Statement The ALTER TABLE statement is used to add, delete, or modify columns in an existing table. The ALTER TABLE statement is also used to add and drop various constraints on an ex…
SQL Constraints SQL constraints are rules for data in a table. Constraints are used to prevent insertion of invalid data in a table, and ensures the accuracy and reliability of the data in the table.…
SQL NOT NULL Constraint The NOT NULL constraint enforces a column to NOT accept NULL values. This enforces a field to always contain a value, which means that you cannot insert a new record, or updat…
SQL UNIQUE Constraint The UNIQUE constraint ensures that all values in a column are unique. Both the UNIQUE and PRIMARY KEY constraints provide a guarantee for uniqueness for a column or set of colum…
SQL PRIMARY KEY Constraint
SQL FOREIGN KEY Constraint The FOREIGN KEY constraint establishes a link between two tables, and prevents action that will destroy the link between them. A FOREIGN KEY is a column in a table that ref…
SQL CHECK Constraint The CHECK constraint is used to ensure that the values in a column satisfies a specific condition. The CHECK constraint evaluates the data to TRUE or FALSE. If the data evaluates…
SQL DEFAULT Constraint The DEFAULT constraint is used to automatically insert a default value for a column, if no value is specified. The default value will be added to all new records (if no other v…
SQL CREATE INDEX Statement The CREATE INDEX statement is used to create indexes on tables in databases, to speed up data retrieval. The users cannot see the indexes, they are just used to speed up se…
SQL AUTO INCREMENT Field
SQL Working With Dates
SQL CREATE VIEW Statement An SQL view is a virtual table based on the result-set of an SQL statement. An SQL view contains rows and columns, just like a real table. The fields in the view are fields…
SQL Injection SQL injection is a code injection technique that can destroy your database. SQL injections are a common web hacking technique. SQL injections are when attackers insert malicious SQL cod…
SQL Parameters - Prevent SQL Injection SQL parameters (Parameterized Queries) can be used to protect a web site from SQL injections. A parameterized query is a SQL statement that uses placeholders in…
SQL Prepared Statements - Prevent SQL Injection SQL prepared statements can be used to protect a web site from SQL injections. Prepared statements seperates the query structure (the SQL) from the act…
SQL Hosting