Search results
Results from the Health.Zone Content Network
Aggregate function. In database management, an aggregate function or aggregation function is a function where multiple values are processed together to form a single summary statistic . (Figure 1) Entity relationship diagram representation of aggregation. Common aggregate functions include: Average (i.e., arithmetic mean) Count. Maximum. Median.
In relational databases a virtual column is a table column whose value(s) is automatically computed using other columns values, or another deterministic expression. Virtual columns are defined of SQL:2003 as Generated Column, and are only implemented by some DBMSs, like MariaDB, SQL Server, Oracle, PostgreSQL, SQLite and Firebird (database server) (COMPUTED BY syntax).
Microsoft Access. Microsoft Access is a database management system (DBMS) from Microsoft that combines the relational Access Database Engine (ACE) with a graphical user interface and software-development tools. It is a member of the Microsoft 365 suite of applications, included in the Professional and higher editions or sold separately.
The star schema is an important special case of the snowflake schema, and is more effective for handling simpler queries. The star schema gets its name from the physical model's resemblance to a star shape with a fact table at its center and the dimension tables surrounding it representing the star's points.
Online analytical processing. In computing, online analytical processing, or OLAP ( / ˈoʊlæp / ), is an approach to quickly answer multi-dimensional analytical (MDA) queries. [1] OLAP is part of the broader category of business intelligence, which also encompasses relational databases, report writing and data mining. [2]
Query optimization. Query optimization is a feature of many relational database management systems and other databases such as NoSQL and graph databases. The query optimizer attempts to determine the most efficient way to execute a given query by considering the possible query plans. [1]
Message authentication code. In cryptography, a message authentication code ( MAC ), sometimes known as an authentication tag, is a short piece of information used for authenticating and integrity -checking a message. In other words, to confirm that the message came from the stated sender (its authenticity) and has not been changed (its integrity).
Access, the successor to ENGLISH, is an English -like query language used in the Pick operating system . The original name ENGLISH is something of a misnomer, as PICK's flexible dictionary structure meant that file and attribute names could be given aliases in any natural language. For instance the command SORT could be given the alias TRIEZ ...