2f_attributes.adoc

Attributes

Introduction

Non-spatial attribute data represents sets (or tuples or rows) of arbitrary relational values that may or may not be relationally linkable to rows in other attribute, feature or tile tables.

Contents

Data

Contents Table - Attributes Row

Requirement 118

The gpkg_contents table SHALL contain a row with a data_type column value of "attributes" for each attributes data table or view.

Attributes User Data Tables

Data

Table Definition

Non-spatial attribute data is stored in user-defined Attribute tables. Attribute sets are rows in an Attribute table. The attributes are columns in a Attribute table. (A GeoPackage is not required to contain any Attribute data tables. Attribute data tables in a GeoPackage may be empty.)

Requirement 119

A GeoPackage MAY contain tables or updatable views containing attribute sets. Every such Attribute table or view in a GeoPackage SHALL have a column with column type INTEGER and PRIMARY KEY AUTOINCREMENT column constraints per GeoPackage Attributes Example Table or View Definition and [example_attributes_table_sql].

The integer primary key of an Attribute table allows attribute sets to be linked to row level metadata records in the gpkg_metadata table by rowid [B5] values in the gpkg_metadata_reference table as described in clause [extension_metadata] below.

Table 1. GeoPackage Attributes Example Table or View Definition

Column Name	Col Type	Column Description	Null	Key
id	INTEGER	Autoincrement primary key	no	PK
text_attribute	TEXT	Text attribute of feature	yes
real_attribute	REAL	Real attribute of feature	yes
boolean_attribute	BOOLEAN	Boolean attribute of feature	yes
raster_or_photo	BLOB	Photo of the area	yes