The first thing needed for annotations is a table that stores them.

These are the CREATE TABLE and CREATE SEQUENCE statements for a table that stores annotations for the customers table used previously:

CREATE TABLE customers_text (

  customers_text_id NUMBER,

  customers_ref NUMBER,

  angle NUMBER,

  cust_text_location SDO_GEOMETRY);

 CREATE SEQUENCE customers_text_seq

  START WITH 1001 INCREMENT BY 1;

As with the parent table (customers), a sequence is created to ensure that the table’s identifier (here: customer_text_id) will be unique when annotations are added or removed in Bentley Map.

Next to the table’s identifier, a column that references the identifier in the root table is specified (customers_ref). The column angle will store the angle that the text is placed under (note: could either be radians or degrees – this can be specified when registering the feature) and the SDO_GEOMETRY field stores the location of the text element.

Like for any spatial table, an entry in the USER_SDO_GEOM_METADATA view and a spatial index are required for Bentley Map to work with the table:

INSERT INTO user_sdo_geom_metadata

  (TABLE_NAME, COLUMN_NAME, DIMINFO, SRID)

 VALUES

  ('CUSTOMERS_TEXT', 'CUST_TEXT_LOCATION',

   SDO_DIM_ARRAY

    (SDO_DIM_ELEMENT('LONG', -180.0, 180.0, 0.5),

    SDO_DIM_ELEMENT('LAT', -90.0, 90.0, 0.5)),

  8307);

 CREATE INDEX customers_text_sidx ON customers_text(cust_text_location)

  INDEXTYPE IS mdsys.spatial_index

   PARAMETERS ('layer_gtype=POINT');