Across
- 1. a set of servers configured to function together. Servers sometimes have differentiated functions and sometimes they do not.
- 4. takes as input queries and data about the documents, columns, or graphs in a database and produces a sequence of operations that retrieve the selected data.
- 6. This schema is a database that allows for documents of different types and forms to exist in the same collection. This term is usually used with reference to document databases.
- 10. the process of saving multiple copies of data in your cluster. This provides for high availability of distributed databases.
- 11. a set of ordered key-value pairs. A key is a unique identifier used to look up a value. A value is an instance of any supported data type, such as a string, number, array, or list.
- 13. With respect to distributed databases, this refers to splitting documents, tables, or graphs and distributing them to different servers. With respect to the CAP theorem, it refers to losing a network connection in a way that leaves parts of the network unreachable from some other parts.
Down
- 2. the process of dividing a database by documents in a document database or by rows in a relational database.
- 3. a technique for improving database performance by storing columns of a relational table in separate, multiple partitions. This is especially helpful when only a subset of columns is read from a row of data and the columns are read from many rows.
- 5. a group of documents. These documents are usually related to the same subject entity, such as employees, products, logged events, or customer profiles.
- 7. a logical subset of a database; usually used to store a set of data based on some attribute of the data.
- 8. document enables document database users to store related data in a single document. This allows the document database to avoid a process called joining in which data from one table, called the foreign key, is used to look up data in another table.
- 9. Document databases do not require data modelers to formally specify the structure of documents. A formal structure specification is known as a schema. Relational databases do require schemas.
- 12. This theorem, also known as Brewer’s theorem after the computer scientist who introduced it, the theorem states that distributed databases cannot have consistency, availability, and partition protection all at the same time.