### Database Schema:
CREATE TABLE IMG_OBJ_ATT (
	IMG_ID	INTEGER	NOT NULL	DEFAULT 0	PRIMARY KEY,
	ATT_CLASS_ID	INTEGER	NOT NULL	DEFAULT 0	PRIMARY KEY,
	OBJ_SAMPLE_ID	INTEGER	NOT NULL	DEFAULT 0	PRIMARY KEY,
	foreign key (OBJ_SAMPLE_ID) references IMG_OBJ (OBJ_SAMPLE_ID),
	foreign key (IMG_ID) references IMG_OBJ (IMG_ID),
	foreign key (ATT_CLASS_ID) references ATT_CLASSES (ATT_CLASS_ID)
);

CREATE TABLE OBJ_CLASSES (
	OBJ_CLASS_ID	INTEGER	NOT NULL	DEFAULT 0	PRIMARY KEY,
	OBJ_CLASS	TEXT	NOT NULL
);

CREATE TABLE ATT_CLASSES (
	ATT_CLASS_ID	INTEGER	NOT NULL	DEFAULT 0	PRIMARY KEY,
	ATT_CLASS	TEXT	NOT NULL
);

CREATE TABLE PRED_CLASSES (
	PRED_CLASS_ID	INTEGER	NOT NULL	DEFAULT 0	PRIMARY KEY,
	PRED_CLASS	TEXT	NOT NULL
);

CREATE TABLE IMG_OBJ (
	IMG_ID	INTEGER	NOT NULL	DEFAULT 0	PRIMARY KEY,
	OBJ_SAMPLE_ID	INTEGER	NOT NULL	DEFAULT 0	PRIMARY KEY,
	OBJ_CLASS_ID	INTEGER	NULL,
	X	INTEGER	NULL,
	Y	INTEGER	NULL,
	W	INTEGER	NULL,
	H	INTEGER	NULL,
	foreign key (OBJ_CLASS_ID) references OBJ_CLASSES (OBJ_CLASS_ID)
);

CREATE TABLE IMG_REL (
	IMG_ID	INTEGER	NOT NULL	DEFAULT 0	PRIMARY KEY,
	PRED_CLASS_ID	INTEGER	NOT NULL	DEFAULT 0	PRIMARY KEY,
	OBJ1_SAMPLE_ID	INTEGER	NOT NULL	DEFAULT 0	PRIMARY KEY,
	OBJ2_SAMPLE_ID	INTEGER	NOT NULL	DEFAULT 0	PRIMARY KEY,
	foreign key (IMG_ID) references IMG_OBJ (IMG_ID),
	foreign key (OBJ2_SAMPLE_ID) references IMG_OBJ (OBJ_SAMPLE_ID),
	foreign key (PRED_CLASS_ID) references PRED_CLASSES (PRED_CLASS_ID),
	foreign key (OBJ1_SAMPLE_ID) references IMG_OBJ (OBJ_SAMPLE_ID)
);

### User's Query:
Define the onion's bounding box on image no. 285930.

### Extra Knowledge:
bounding box refers to (X, Y, W, H); onion refers to OBJ_CLASS = 'onion'; image no.285930 refers to IMG_ID = 285930
SELECT T1.X, T1.Y, T1.W, T1.H FROM IMG_OBJ AS T1 INNER JOIN OBJ_CLASSES AS T2 ON T1.OBJ_CLASS_ID = T2.OBJ_CLASS_ID WHERE T1.IMG_ID = 285930 AND T2.OBJ_CLASS = 'onion'