link overrides table structure

This table includes information on the fields of the network that happen to diverge from their base value (contained in the link table) for any arbitrary period. This feature has not been implemented in POLARIS

Table Structure

Field	Type	NULL allowed	Default Value	Foreign key	Description
link_change_id*	INTEGER	NO			override identifier
link	INTEGER	YES		Link(link)	bi-directional link that it refers to
field	TEXT	NO	‘’		direction (0 for A to B, 1 for B to a)
data_value	TEXT	NO			which value to be set for the period
from_time	INTEGER	NO	0		initial time (in seconds from midnight) in which the override applies
notes	TEXT	YES			any note (not read/used by POLARIS)

(* - Primary key)

The SQL statement for table and index creation is below.

CREATE TABLE IF NOT EXISTS "Link_Overrides" (
    "link_change_id"  INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
    "link"            INTEGER,
    "field"           TEXT    NOT NULL DEFAULT '',
    "data_value"      TEXT    NOT NULL,
    "from_time"       INTEGER NOT NULL DEFAULT 0,
    "notes"           TEXT,

    CONSTRAINT "link_fk" FOREIGN KEY("link") REFERENCES "Link"("link") ON DELETE CASCADE DEFERRABLE INITIALLY DEFERRED
);

create INDEX IF NOT EXISTS "idx_lnk_over_link" ON "link_overrides" ("link");