Customizing options of view of a spatial database |
DBM file (* .dbm) is used to store the parameters of access to the database and settings for the formation of a cartographic view (view) from spatial data from its tables. This file has an XML structure and contains all the necessary settings for the formation of a cartographic view of a spatial database. The structure of the DBM file is given in Appendix 4. Setting the parameters of the DBM file is performed using a special dialog. Options of view of spatial database are divided into several sections. View options This section contains the passport data of the map, in the form of which the operator will be provided with the spatial database view (all options are required):
Customizing a database connection In this section the unique name of set of the options is specified which are responsible for connection to the required DB:
Data selection The section «Select data» contains options that determine the way to access a dataset with spatial information in the database. Access to information in the database is possible in one of two ways: direct access to the table in the database, execution of an arbitrary SQL query. Write back in the database is possible only with the first way. When using an SQL query, access to the database is performed only for reading. Required for filling is the table name or the query text - depending on the selected method.
Description of query result The section «Description of query result» contains the parameters that determine the processing of information in the dataset of the spatial database - the purpose of the dataset fields, their correspondence to the semantics of objects in the cartographic representation, the way of specifying the external view of objects. Mandatory fields for filling are the field names of the unique identifier and metric. Also you must specify and customize one of options of establishing the conventional view of object in cartographical representation (by code or by object key).
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