Player-defined priority storage

Added the events.custom_priorities that ought to store player-defined
priorities for event types which support it.

legacyworlds-server-data/db-structure/parts/030-data/170-events.sql

@@ -27,6 +27,12 @@ CREATE TABLE events.event_definitions(
 	evdef_adjustable	BOOLEAN NOT NULL
 );
 
+/* Unique index allowing the custom priorities table to reference only
+ * adjustable event types.
+ */
+CREATE UNIQUE INDEX idx_evdef_adjustables
+	ON events.event_definitions( evdef_id , evdef_adjustable );
+
 GRANT SELECT ON events.event_definitions TO :dbuser;
 
 
@@ -161,6 +167,45 @@ ALTER TABLE events.field_definitions
 GRANT SELECT ON events.field_definitions TO :dbuser;
 
 
+/*
+ * Custom event priorities
+ * -----------------------
+ * 
+ * This table stores player-defined event priority overrides. Only events
+ * with custom priorities may be present in this table.
+ */
+DROP TABLE IF EXISTS events.custom_priorities CASCADE;
+CREATE TABLE events.custom_priorities(
+	/* Identifier of the event type */
+	evdef_id			VARCHAR(48) NOT NULL ,
+
+	/* Used in reference to the event types - forces this table to
+	 * reference only events that *can* be customised.
+	 */
+	evdef_adjustable	BOOLEAN NOT NULL DEFAULT TRUE
+							CHECK( evdef_adjustable ) ,
+
+	/* Account identifier */
+	address_id			INT NOT NULL ,
+	
+	/* Custom priority */
+	evcp_priority		INT NOT NULL
+							CHECK( evcp_priority BETWEEN 0 AND 4 ) ,
+
+	/* Use the event identifier and "adjustable" set value as the primary
+	 * key. The advantage is that we get an index on both fields.
+	 */
+	PRIMARY KEY( evdef_id , evdef_adjustable )
+);
+
+ALTER TABLE events.custom_priorities
+	ADD CONSTRAINT fk_evcp_evdef
+		FOREIGN KEY ( evdef_id , evdef_adjustable )
+			REFERENCES events.event_definitions ( evdef_id , evdef_adjustable );
+
+GRANT SELECT ON events.custom_priorities TO :dbuser;
+
+
 /*
  * Event identifier sequence
  * -------------------------