Tuples (or records) are individual entries in a relation (or table). All tuples in the same relation have the same named fields. In a diagram, such as in Figure 1 above, relations can be displayed as data in tabular form, as the relations provided in the figure demonstrate. The PrivatePerson table has three tuples; the Surname attribute value for the first tuple shown is “Garcia.” Tuples can be specifically queried using tuple selection.
In relational data models, a database is viewed as a collection of relations, also commonly referred to as tables. A table or relation is itself a collection of tuples (or records). In fact, each table is a collection of tuples that are similarly shaped. By this, we mean that a tuple has a fixed number of named fields (also known as attributes).
Describe and explain the structure and components of a relational data model and a relational database (level 1 and 2). Describe and explain what a Database Management System (DBMS) is and how it links to a GIS.
Explain the basic concepts of data retrieval (attribute and spatial queries) and formulate queries to make a selection on attributes and geospatial data from a spatial database.