# Module org.apache.sis.storage.sql

module org.apache.sis.storage.sql
Data store for features in a SQL spatial database. This module expects a spatial schema conforms to the conventions described in the OGC Simple feature access - Part 2: SQL option international standard, also known as ISO 19125-2.

## Difference with Geopackage

Compared to the OGC Geopackage standard, this SQL module has the following differences:

- There is no discovery mechanism (e.g., no `"gpkg_contents"` table). The tables to use as resource definitions must be specified explicitly.
- Each feature table can contain an arbitrary number of geometry columns, including zero. By contrast, Geopackage requires each feature table to have exactly one geometry column.
- As a consequence of the above, this module makes no distinction between "features" table and "attributes" table.
- This module supports complex features, i.e. features having associations to other features. The associations are discovered automatically by following the foreigner keys.
- Primary keys are optional. If present, they can be of any type (not necessarily integers) and can be composite (made of many columns). By contrast, Geopackage mandates primary keys made of exactly one column of integers.

Since:
  1.0

- ## Packages

  Exports
  Package
  Description
  org.apache.sis.storage.sql
  Data store capable to read and write features using a JDBC connection to a database.
  Indirect Exports
  From
  Packages
  org.apache.sis.feature
  org.apache.sis.coverage org.apache.sis.coverage.grid org.apache.sis.feature org.apache.sis.feature.builder org.apache.sis.filter org.apache.sis.image org.apache.sis.index.tree
  org.apache.sis.metadata
  org.apache.sis.metadata org.apache.sis.metadata.iso org.apache.sis.metadata.iso.acquisition org.apache.sis.metadata.iso.citation org.apache.sis.metadata.iso.constraint org.apache.sis.metadata.iso.content org.apache.sis.metadata.iso.distribution org.apache.sis.metadata.iso.extent org.apache.sis.metadata.iso.identification org.apache.sis.metadata.iso.lineage org.apache.sis.metadata.iso.maintenance org.apache.sis.metadata.iso.quality org.apache.sis.metadata.iso.spatial org.apache.sis.metadata.sql org.apache.sis.util.iso org.apache.sis.xml
  org.apache.sis.referencing
  org.apache.sis.coordinate org.apache.sis.geometry org.apache.sis.io.wkt org.apache.sis.parameter org.apache.sis.referencing org.apache.sis.referencing.crs org.apache.sis.referencing.cs org.apache.sis.referencing.datum org.apache.sis.referencing.factory org.apache.sis.referencing.factory.sql org.apache.sis.referencing.operation org.apache.sis.referencing.operation.builder org.apache.sis.referencing.operation.matrix org.apache.sis.referencing.operation.transform
  org.apache.sis.storage
  org.apache.sis.storage org.apache.sis.storage.aggregate org.apache.sis.storage.event org.apache.sis.storage.modifier org.apache.sis.storage.tiling
  org.apache.sis.util
  org.apache.sis.io org.apache.sis.math org.apache.sis.measure org.apache.sis.setup org.apache.sis.util org.apache.sis.util.collection org.apache.sis.util.logging

- ## Modules

  Requires
  Modifier
  Module
  Description
  transitive
  org.apache.sis.storage
  Raster imagery and geometry features.
  Indirect Requires
  Modifier
  Module
  Description
  transitive
  org.apache.sis.feature
  Raster imagery and geometry features.
  transitive
  org.apache.sis.metadata
  Implementations of metadata derived from ISO 19115.
  transitive
  org.apache.sis.referencing
  Referencing by coordinates.
  transitive
  org.apache.sis.util
  Units of measurement and miscellaneous utility methods required by Apache SIS.