A , also known as a calculated field, is a field that is not directly stored in a table, but is instead created based on the values of other fields using mathematical or logical operations. are variables that can be passed into a program or a function to customize its behavior or output. In the context of databases, a ]] refers to a SQL query that includes s for values that are supplied by the user or application at runtime. This approach helps prevent , such as , where malicious code is injected into user-provided data to manipulate or gain unauthorized access to the database.
, sometimes called placeholders, are used within a parameterized query to designate where user-supplied values should be inserted. When executing the query, the actual values are substituted for these markers, ensuring that they are treated as data rather than executable code. A query]] combines the concepts of a database view and a query, providing a that can be used for and manipulation.
A database view is a saved query that creates a virtual table, which can be queried like any other table in the database. With a view, you can perform operations such as aggregating data, ing tables, ing records, ing results, applying logic, and using subqueries. and clauses are commonly used to perform operations, while is used to retrieve unique values from a column. Additionally, the keyword is often employed to restrict the number of rows returned by a query.
Keywords
database [[view | database | group by | parameter markers | placeholder | sort | aggregate | data retrieval | distinct | sql injection | having | limit | parameters | derived field | filter | parameterized [[query | join | virtual table | conditional | injection attacks |
