Explore chapters and articles related to this topic
Big Data in Medical Image Processing
Published in R. Suganya, S. Rajaram, A. Sheik Abdullah, Big Data in Medical Image Processing, 2018
R. Suganya, S. Rajaram, A. Sheik Abdullah
Document databases can scale horizontally very well for more than 1000 patients in the hospital. Data can be stored over many thousands of computers and the system will perform well. This is often referred to as sharding. Relational databases are not well suited to scaling in this fashion. Relational DBs are more suited towards scaling vertically (i.e., adding more memory, storage, etc.). Seeing as there’s a limit to how many resources one can fit inside one machine, there could come a point where horizontal scaling becomes the only option. Document stores don’t have foreign keys, like relational databases have. Foreign keys are used by relational databases to enforce relationships between tables. If a relationship needs to be established with a document database, it would need to be done at the application level.
General introduction
Published in Adedeji B. Badiru, Handbook of Industrial and Systems Engineering, 2013
The idea that database systems should present the user with a view of data organized as tables called relations was originally proposed by Codd (1979). Each relation is made up of attributes. Attributes are values describing properties of an entity, a concrete object in its reality. Furthermore, the connections among two or more sets of entities are called relationships. The idea of a key on a table is central to the relational model. The purpose of a key is to identify each row uniquely. A primary key is the attribute (or combination of attributes) that uniquely identifies one row or record. On the other hand, a foreign key is the attribute (or combination of attributes) that appears as a primary key in another table. Foreign key relationships provide the basis for establishing relationships across tables in a relational database.
Introduction to the SAS- and R-Based Table-Driven Environment
Published in Tanya Kolosova, Samuel Berestizhevsky, Supervised Machine Learning, 2020
Tanya Kolosova, Samuel Berestizhevsky
Another term that is used in the relational data model is a foreign key. Foreign keys are used to “link” related tables together. A foreign key is a column, or set of columns, that defines a data value that must exist in some other relational table as that other table’s primary key. A relational data model maintains relational “links” by matching primary key values in one table with identical foreign key values in a related table. Note that a table can only have one primary key, but can have any number of foreign keys (since one table can be related to any number of other tables).
Secure data outsourcing in presence of the inference problem: issues and directions
Published in Journal of Information and Telecommunication, 2021
Adel Jebali, Salma Sassi, Abderrazak Jemai
Authors in Bkakria et al. (2013a) have built on Bkakria et al. (2013b) to propose an approach that securely outsourcing data based on fragmentation and encryption. It also enforces access control when querying data by resorting to query privacy technique. The approach treated the case of multi-relations database and a new inter-table confidentiality constraints was introduced. It assumes that the distributed servers could collude to break data confidentiality so the connection between servers is supposed to be based on primary-key/foreign key. In addition, the query evaluation model which is based on private information retrieval ensure data unlinkability performed by malicious user using semi join query. Even though, the proposed technique enforces database schema to be normalized, and generates a huge number of confidentiality constraints due to the transformation of inter-table constraints to singleton and association constraints which could affect the quality of the fragmentation algorithm. In addition, more generic queries should be considered.
Hybrid state transactional database for product lifecycle management features in a multi-engineer synchronous heterogeneous CAD environment
Published in Computer-Aided Design and Applications, 2018
Devin Shumway, Jonathan Sadler, John L. Salmon
Referential integrity is the process of enforcing every database table to have all foreign keys point to a valid reference [9, 15]. Most database engines will automatically handle references; however, this is only effective when the database has been set up in a way to handle every possible rule. Enforcement of foreign key references in the new NPCF database is vital for keeping the database stable. Referential integrity will help the database recognize corrupted or incomplete data which in turn will be rejected from the database. Rejected data will remain on the client that attempted to send it instead of propagating through each client that is currently in the multi-user session. Referential integrity will also protect the database from corrupt data existing in the part history thus allowing it to be more accurate in storing information. Further checks are implemented on the client side in each CAD system’s plug-in to check that data sent to the database is consistent with the feature the user is trying to create.
A prototype HGIS for managing earthquake data from historical documents
Published in Geomatics, Natural Hazards and Risk, 2019
Federica Migliaccio, Mario Locati, Daniela Carrion, Livia Manenti, Marco Martoccia
Subsequently, information represented in the ERD has been translated in a logical scheme efficiently describing the information content of the conceptual model. The data types, defined for all the attributes of the entities, are either integer, varchar or double. Then, besides defining primary keys for all entities of the database, foreign keys have been introduced to implement associations between entities with one-to-many cardinality (e.g. “Place_names” contains a foreign key corresponding to the primary key of “Damaged_places”). The logical model of the proposed database, designed by SQL Power Architect Community Edition, a Free and Open Source tool by SQL Power Group Inc., is represented in Figure 2.