Tuple selection works like a filter: it allows tuples that meet the selection condition to pass and disallows tuples that do not meet the condition. The operator is given some input relation, as well as a selection condition about tuples in the input relation. A selection condition is a truth statement about a tuple’s attribute values, such as AreaSize > 1000. For some tuples in Parcel, this statement will be true and for others it will be false. Tuple selection on the Parcel relation with this condition will result in a set of Parcel tuples for which the condition is true.
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.