Queries

Queries can be made on the geometries (SIOSE or SIOSE AR polygons) or the covers and uses of interest (from alphanumeric tables), subsequently transmitting the selection to the polygons that meet the criteria of the queries made.

• Queries on polygons [T_POLIGONES], [T_USES] or [T_COMBINED]:
  
  In a Geographic Information System (GIS) the polygons that interest us (by surface, location, fields, etc.) are selected in the attribute table [T_POLIGONES], [T_USES] or [T_COMBINED]. SIOSE AR has the possibility of selecting by majority fields of covers and uses within each polygon.
  
  Obtain additional information corresponding to the covers [T_POLYGONS], in their corresponding records in the table of covers [T_VALUES] by means of the common field ID_POLYGON. To do this, both tables must first be related with a 1:N relationship, because for each SIOSE polygon there is more than one record in the table [T_VALUES] that describes its content.
  
  In SIOSE or SIOSE AR, joins between the two tables are not usually performed to prevent losing information, since as a result of this operation only one record of [T_VALUES] would be extracted for each record of [T_POLYGONS], type 1:1.
   
• Detailed queries on covers or uses:
  
  Queries are made on the cover table [T_VALUES] using a GIS or database management software (Access, Oracle, etc.), the result of the query being a selection on [T_VALUES] or a new table.
  
  To visualise the result of the query on the SIOSE polygons in a GIS it is necessary to previously list that result on [T_VALUES] with [T_POLYGONS] by means of the common field ID_POLYGON.
  
  For uses it would be the same procedure, but worked with the alphanumeric table [T_USES_MULTIPLE_AGRUPED_USES] and the geomety of [T_USES].
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• Statistical queries:
  
  By selecting the different covers in the table [T_VALUES] or [T_MULTIPLE_AGRUPTED_USES] it is possible to obtain statistical calculations by relating it to the table T_POLIGONES or T_USES. Some examples are shown below.

Examples of queries on the SIOSE database are described in detail in the technical documentation of the project, under "Documentation".