Add parent_id column for alias identity support

Migration and initial schemas for linking alias identities to parent
accounts via a nullable parent_id foreign key.

SQL/mysql.initial.sql

@@ -11,6 +11,9 @@ CREATE TABLE IF NOT EXISTS `ident_switch`
 		int UNSIGNED
 		NOT NULL
 		UNIQUE,
+	`parent_id`
+		int UNSIGNED
+		DEFAULT NULL,
 	`username`
 		varchar(64),
 	`password`
@@ -80,5 +83,6 @@ CREATE TABLE IF NOT EXISTS `ident_switch`
 	CONSTRAINT `fk_identity_id` FOREIGN KEY (`iid`) REFERENCES `identities`(`identity_id`) ON DELETE CASCADE ON UPDATE CASCADE,
 	PRIMARY KEY(`id`),
 	INDEX `IX_ident_switch_user_id`(`user_id`),
-	INDEX `IX_ident_switch_iid`(`iid`)
+	INDEX `IX_ident_switch_iid`(`iid`),
+	INDEX `IX_ident_switch_parent_id`(`parent_id`)
 );

SQL/mysql/2026021100.sql

@@ -0,0 +1,9 @@
+-- Add alias support: parent_id links an alias identity to a parent account
+ALTER TABLE `ident_switch`
+	ADD `parent_id`
+		int UNSIGNED
+		DEFAULT NULL
+		AFTER `iid`;
+
+ALTER TABLE `ident_switch`
+	ADD INDEX `IX_ident_switch_parent_id` (`parent_id`);

SQL/postgres.initial.sql

@@ -12,6 +12,9 @@ CREATE TABLE ident_switch
 		NOT NULL
 		REFERENCES identities(identity_id) ON DELETE CASCADE ON UPDATE CASCADE
 		UNIQUE,
+	parent_id
+		integer
+		DEFAULT NULL,
 	username
 		varchar(64),
 	password
@@ -81,3 +84,4 @@ CREATE TABLE ident_switch
 
 CREATE INDEX IX_ident_switch_user_id ON ident_switch(user_id);
 CREATE INDEX IX_ident_switch_iid ON ident_switch(iid);
+CREATE INDEX IX_ident_switch_parent_id ON ident_switch(parent_id);

SQL/postgres/2026021100.sql

@@ -0,0 +1,5 @@
+-- Add alias support: parent_id links an alias identity to a parent account
+ALTER TABLE ident_switch
+	ADD parent_id integer DEFAULT NULL;
+
+CREATE INDEX IX_ident_switch_parent_id ON ident_switch(parent_id);

SQL/sqlite.initial.sql

@@ -12,6 +12,9 @@ CREATE TABLE ident_switch
 		NOT NULL
 		REFERENCES identities(identity_id) ON DELETE CASCADE ON UPDATE CASCADE
 		UNIQUE,
+	parent_id
+		integer
+		DEFAULT NULL,
 	username
 		varchar(64),
 	password
@@ -80,3 +83,4 @@ CREATE TABLE ident_switch
 );
 CREATE INDEX IX_ident_switch_user_id ON ident_switch(user_id);
 CREATE INDEX IX_ident_switch_iid ON ident_switch(iid);
+CREATE INDEX IX_ident_switch_parent_id ON ident_switch(parent_id);

SQL/sqlite/2026021000.sql

@@ -19,6 +19,9 @@ CREATE TABLE ident_switch
 		NOT NULL
 		REFERENCES identities(identity_id) ON DELETE CASCADE ON UPDATE CASCADE
 		UNIQUE,
+	parent_id
+		integer
+		DEFAULT NULL,
 	username
 		varchar(64),
 	password
@@ -87,6 +90,7 @@ CREATE TABLE ident_switch
 );
 CREATE INDEX IX_ident_switch_user_id ON ident_switch(user_id);
 CREATE INDEX IX_ident_switch_iid ON ident_switch(iid);
+CREATE INDEX IX_ident_switch_parent_id ON ident_switch(parent_id);
 
 INSERT OR ROLLBACK INTO
 	ident_switch (

SQL/sqlite/2026021100.sql

@@ -0,0 +1,4 @@
+-- Add alias support: parent_id links an alias identity to a parent account
+ALTER TABLE ident_switch ADD parent_id integer DEFAULT NULL;
+
+CREATE INDEX IF NOT EXISTS IX_ident_switch_parent_id ON ident_switch(parent_id);