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A database dump contains a record of the table structure and/or the data from a database and is usually in the form of a list of SQL statements ("SQL dump"). A database dump is most often used for backing up a database so that its contents can be restored in the event of data loss. Corrupted databases can often be recovered by analysis of the dump.
Meanwhile, COALESCE simplifies the process of handling NULL values by returning the first non-NULL value in a given list of expressions, which is especially useful in scenarios where data might be incomplete or missing. Furthermore, SQL's support for three-valued logic (True, False, Unknown) introduces nuances when handling NULL values in ...
One states an action with an action stub. An action entry specifies whether (or in what order) the action is to be performed. A decision table separates the data (that is the condition entries and decision/action entries) from the decision templates (that are the condition stubs, decision/action stubs, and the relations between them).
Decision tables are a concise visual representation for specifying which actions to perform depending on given conditions. Decision table is the term used for a Control table or State-transition table in the field of Business process modeling ; they are usually formatted as the transpose of the way they are formatted in Software engineering .
The SQL SELECT statement returns a result set of rows, from one or more tables. [1] [2] A SELECT statement retrieves zero or more rows from one or more database tables or database views. In most applications, SELECT is the most commonly used data manipulation language (DML) command.
One method of hiding rows in tables (or other structures within tables) uses HTML directly. [1] HTML is more complicated than MediaWiki table syntax, but not much more so. In general, there are only a handful of HTML tags you need to be aware of
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 schemas .
A relational schema R is in Boyce–Codd normal form if and only if for every one of its functional dependencies X → Y, at least one of the following conditions hold: [5] X → Y is a trivial functional dependency (Y ⊆ X), X is a superkey for schema R. [5]