Metadata Table View Text .1

Copyright © 2007 Open Geospatial Consortium, Inc. All Rights Reserved. Table 3: Text metadata attributes FIELD DEFINITION COMMENT F_TABLE_CATALOG F_TABLE_SCHEMA F_TABLE_NAME Name of the table in which the text type values are stored. Databases have format for this based on SQL:1999. F_TEXT_COLUMN_NAME Name of the column in which the text type value are stored. Databases have format for this based on SQL:1999. This column in the feature table described above must be of type ANNOTATION_TEXT. A_TEXT_DEFAULT_MAP_BASE_SCALE The base map scale for which the text will be displayed A_TEXT_DEFAULT_EXPRESSION This column allows the actual text of a text object to come from data outside the text object VALUE field. Any valid database column expression resulting in a string is acceptable. The expression is evaluated for the each row. If this field is null, the individual text objects may have their own embedded text or nothing shall be displayed. Any embedded text shall override this expression value. During query to support display, client applications should add this expression to their select list so that any returned records will have the information needed to evaluate this expression without round tripping back to the database. . Note that this is the one case where the data critical to the display of text is stored outside the text object or metadata. It should be obvious to anyone changing the VALUE field that they are changing the text object. It may not be obvious to someone updating a column covered by the text expression that they are affecting the text object display. A_TEXT_DEFAULT_ATTRIBUTES As many text attributes may be common in one table, the database may store the common ones once here and allow for individual row record overrides. The Text Style, Layout and Leader Line Style described below may be stored in the metadata as well as the individual rows. Any values in the individual rows shall override the metadata values. The resulting attributes are an overlay of the metadata attributes and individual row attribute values. Copyright © 2007 Open Geospatial Consortium, Inc. All Rights Reserved. xix 7 Clause component specifications

7.1 Components — Implementation of feature tables based on predefined data types

7.1.1 Conventions

Table components are described in the context of a CREATE TABLE statement. Implementations may use base tables with different names and properties, exposing these components as updateable views, provided that the base tables defined by the implementation enforce the same constraints. Table names and column names have been restricted to 18 characters in length to allow for the widest possible implementation. 7.1.2 Spatial reference system information 7.1.2.1 Component overview The Spatial Reference Systems table, which is named SPATIAL_REF_SYS, stores information on each spatial reference system used in the database.

7.1.2.2 Table constructs

The following CREATE TABLE statement creates an appropriately structured SPATIAL_REF_SYS table. This table may be an updatable view of an implementation-specific table. Implementations shall either use this table format or provide stored procedures to create, to populate and to maintain this table CREATE TABLE SPATIAL_REF_SYS SRID INTEGER NOT NULL PRIMARY KEY, AUTH_NAME CHARACTER VARYING, AUTH_SRID INTEGER, SRTEXT CHARACTER VARYING2048

7.1.2.3 Field description

These fields are described as follows: a SRID — an integer value that uniquely identifies each Spatial Reference System within a database; b AUTH_NAME — the name of the standard or standards body that is being cited for this reference system. EPSG would be an example of a valid AUTH_NAME; Copyright © 2007 Open Geospatial Consortium, Inc. All Rights Reserved. c AUTH_SRID — the ID of the Spatial Reference System as defined by the Authority cited in AUTH_NAME; d SRTEXT — The Well-known Text Representation of the Spatial Reference System.

7.1.2.4 Exceptions, errors and error codes

Error handling shall be accomplished by using the standard SQL status returns. 7.1.3 Geometry columns information 7.1.3.1 Component overview The GEOMETRY_COLUMNS table provides information on the feature table, spatial reference, geometry type, and coordinate dimension for each Geometry column in the database. This table may be an updatable view of an implementation-specific table. Implementations shall either use this table format or provide stored procedures to create, to populate and to maintain this table