DBMS: Many-to-Many Relationship (Definitions)

"Multiple instances of one entity are associated with one or more instances of another entity." (Owen Williams, "MCSE TestPrep: SQL Server 6.5 Design and Implementation", 1998)

"A relationship between two tables in which rows in each table have multiple matching rows in the related table. Many-to-many relationships are maintained by using a third table called a junction table." (Microsoft Corporation, "SQL Server 7.0 System Administration Training Kit", 1999)

"A logical data relationship in which the value of one data element can exist in combination with many values of another data element, and vice versa." (Ralph Kimball & Margy Ross, "The Data Warehouse Toolkit" 2nd Ed., 2002)

"A relationship type between tables in a relational database where one row of a given table may be related to many rows of another table, and vice versa. Many-to-many relationships are often resolved with an intermediate associative table." (Bob Bryla, "Oracle Database Foundations", 2004)

"This type of relationship occurs when many rows or things in an entity (many instances of an entity) are associated with many rows or things in another entity. This type of relationship is not uncommon in the real world. SQL Server doesn't actually allow direct implementation of many-to-many relationships; nevertheless, you can do so by creating two one-to-many relationships to a new entity." (Thomas Moore, "EXAM CRAM™ 2: Designing and Implementing Databases with SQL Server 2000 Enterprise Edition", 2005)

"A relationship where one object of one type may correspond to many objects of another type and vice versa. For example, one COURSE may include many STUDENTs and one STUDENT may be enrolled in many COURSEs. Normally you implement this kind of relationship by using an intermediate table that has one-to-many relationships with the original tables." (Rod Stephens, "Beginning Database Design Solutions", 2008)

"A relationship between two entities in a database such that each instance of the first entity can be related to many instances of the second and each instance of the second entity can be related to many instances of the first." (Jan L Harrington, "Relational Database Design and Implementation" 3rd Ed., 2009)

"A relationship where an occurrence of each entity class may be associated with one or more occurrences of the other entity class." (David C Hay, "Data Model Patterns: A Metadata Map", 2010)

"One of three types of relationships (associations among two or more entities) in which one occurrence of an entity is associated with many occurrences of a related entity and one occurrence of the related entity is associated with many occurrences of the first entity." (Carlos Coronel et al, "Database Systems: Design, Implementation, and Management" 9th Ed., 2011)

"A link between two entities in which the cardinality of both sides of the relationship is multiple." (Craig S Mullins, "Database Administration: The Complete Guide to DBA Practices and Procedures", 2012)

"A relationship between two tables in which one row in one table can relate to many rows in another table." (Microsoft, "SQL Server 2012 Glossary", 2012)