Relational functions

Relational functions are used to relate data items of different domain units like lookup or rjoin or create new domain units like unique. For the spatial counterparts of a join, and how they lead on to allocation, see Spatial joins and allocation.

Selection functions can be found on the separate page: Selection functions.

• id - index numbers
• mapping - to map attributes between domain units

• lookup - using a relation to find the relevant entries
• rlookup - using a foreign key attribute to make a relation
• rlookup_with_null - as rlookup(relational function), but a null value is looked up in a null entry of the target values instead of resulting in null
• rjoin - using a foreign key to find the relevant entries, combining lookup and rlookup
• join_equal_values - find all combinations of A and B where A.x_rel is equal to B.x_rel
• join_equal_values_uint8 - is the join_equal_values variant with a uint8 result domain
• join_equal_values_uint16 - is the join_equal_values variant with a uint16 result domain
• join_equal_values_uint32 - is the join_equal_values variant with a uint32 result domain
• join_equal_values_uint64 - is the join_equal_values variant with a uint64 result domain
• join_equal_values_uint8_16_32_64 - find all combinations of A and B where A.x_rel is equal to B.x_rel, resulting in a domain unit with the explicit value type
• pareto_optimal - the elements that are Pareto-optimal within their partition on one or more minimised criteria: the front per group by a sort and a sweep, instead of a self-join of the partition with itself
• pareto_optimal_eps - as pareto_optimal, with a relative tolerance per criterion (epsilon-dominance), to thin a front
• join_near_values - creates a new unit with points nearby other points
• join_near_values_uint8, join_near_values_uint16, join_near_values_uint32, join_near_values_uint64 - join_near_values variants with a typed result domain

• index - an index number based on a sort order
• direct_index

• invert - inverts a relation
• invertAll - inverts a relation with linked list for one-to-many navigation

• collect_attr_by_org_rel - collects a set of attributes to a new domain unit, using an org_rel attribute (lookup)
• collect_attr_by_cond - collects a set of attributes to a new domain unit, using a condition
• collect_spec - as above, with the choice of org_rel/condition and the collection scope taken from the first argument
• table_spec - as collect_spec, but returns the supplied selection domain as a new table with the collected attributes directly beneath it
• collect_by_cond - collects an attributes to a new domain unit, using a condition
• recollect_by_cond - recollects attribute values of a selection back to an original set using the condition for the selection.
• collect_by_org_rel - collects values via an org_rel relation; synonymous with lookup (the arrow/array-index operator)
• subindex - refines an index: within runs of an equal primary key, the elements are ordered by the secondary values
• ordinal - passes the ordinal value of an attribute through (identity on numeric attributes)

• unique - configures a new unit, based on the unique values
• unique_uint8 - is the unique variant with a uint8 result domain
• unique_uint16 - is the unique variant with a uint16 result domain
• unique_uint32 - is the unique variant with a uint32 result domain
• unique_uint64 - is the unique variant with a uint64 result domain
• unique_uint8_with_null - is the unique variant with a uint8 result domain that keeps a null entry
• unique_uint16_with_null - is the unique variant with a uint16 result domain that keeps a null entry
• unique_uint32_with_null - is the unique variant with a uint32 result domain that keeps a null entry
• unique_uint64_with_null - is the unique variant with a uint64 result domain that keeps a null entry
• unique_with_null - is the unique variant that keeps a null entry when the input contains null values
• unique_uint8_16_32_64 - configures a new unit, based on the unique values, with a uint8_16_32_64 values unit
• union - obsolete, only in use for backward compatibility
• union_unit - configures a new unit, based on the union of other units
• union_unit_uint8_16_32_64 - configures a new unit, based on the union of other units, with a uint8_16_32_64 values unit
• union_unit_uint8, union_unit_uint16, union_unit_uint32, union_unit_uint64 - union_unit variants with a typed result domain
• union_data - configures a new attribute, based on the union of other data items
• combine_uint8 - is the combine variant with a uint8 result domain
• combine_uint16 - is the combine variant with a uint16 result domain
• combine_uint32 - is the combine variant with a uint32 result domain
• combine_uint64 - is the combine variant with a uint64 result domain
• combine_unit_uint8 - is the combine variant without subitems, with a uint8 result domain
• combine_unit_uint16 - is the combine variant without subitems, with a uint16 result domain
• combine_unit_uint32 - is the combine variant without subitems, with a uint32 result domain
• combine_unit_uint64 - is the combine variant without subitems, with a uint64 result domain
• combine_unit - is the combine variant without subitems
• ordered_union_data - union_data variant, stating that all unioned values are non-decreasing; registered operator name ordererd_union_data (sic)
• combine - configures a new unit, based on the Cartesian product of other units
• combine_unit_uint8_16_32_64 - configures a new unit, without subitems, based on the Cartesian product of other units, with a uint8_16_32_64 values unit
• combine_uint8_16_32_64 - configures a new unit, based on the Cartesian product of other units, with a uint8_16_32_64 values unit
• combine_data - configures a new attribute, based on the Cartesian product of other data items
• combine_rel - the relation to one factor of a combined unit, per element: combine_rel(x_rel, position), or first_rel(x_rel) to sixteenth_rel(x_rel)

• merge - merges the values of a data item, based on an option data item

• overlay - an uint16 domain unit with the unique values of multiple grid attributes
• overlay32 - an uint32 domain unit with the unique values of multiple grid attributes
• overlay64 - an uint64 domain unit with the unique values of multiple grid attributes