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This is also known as a Horizontal Partition, restricting rows output by a query according to specified conditions. With more than one table, the result set will be every combination of rows. So if two tables are T1 and T2, SELECT * FROM T1, T2 will result in every combination of T1 rows with every T2 rows. E.g., if T1 has 3 rows and T2 has 5 ...
Predicates, which specify conditions that can be evaluated to SQL three-valued logic (3VL) (true/false/unknown) or Boolean truth values and are used to limit the effects of statements and queries, or to change program flow. Queries, which retrieve the data based on specific criteria. This is an important element of SQL.
SQLyog works on the Windows platform ranging from Windows Vista [10] to Windows 10. (Windows 9x/ME support was removed in version 5.0, Windows 2000 support stopped with version 8.6, and Windows XP support ended with version 12.5.) It has also been made to work under Linux and various Unixes (including macOS) using the Wine environment. [11]
In addition to basic equality and inequality conditions, SQL allows for more complex conditional logic through constructs such as CASE, COALESCE, and NULLIF.The CASE expression, for example, enables SQL to perform conditional branching within queries, providing a mechanism to return different values based on evaluated conditions.
It was developed by MySQL AB and later by Sun Microsystems and released under the GPL. Development on the GUI Tools bundle has stopped, and is now [when?] only preserved under the Download Archives of the MySQL site. [9] The GUI Tools bundle has been superseded by MySQL Workbench, and reached its End-of-Life with the beta releases of MySQL ...
MariaDB is intended to maintain high compatibility with MySQL, with exact matching with MySQL APIs and commands, allowing it in many cases to function as a drop-in replacement for MySQL. However, new features are diverging. [7] It includes new storage engines like Aria, ColumnStore, and MyRocks.
An example of a data-integrity mechanism is the parent-and-child relationship of related records. If a parent record owns one or more related child records all of the referential integrity processes are handled by the database itself, which automatically ensures the accuracy and integrity of the data so that no child record can exist without a parent (also called being orphaned) and that no ...
In databases, a partial index, also known as filtered index is an index which has some condition applied to it so that it includes a subset of rows in the table.. This allows the index to remain small, even though the table may be rather large, and have extreme selectivity.