1 files changed, 1 insertions, 0 deletions
diff --git a/initialize.sql b/initialize.sql
index 84a37a9..3df2d49 100644
--- a/initialize.sql
+++ b/initialize.sql
@@ -5,6 +5,7 @@ CREATE TABLE IF NOT EXISTS image(
 	thumbw   INTEGER,           -- cached thumbnail width, if known
 	thumbh   INTEGER,           -- cached thumbnail height, if known
 	dhash    INTEGER,           -- uint64 perceptual hash as a signed integer
+	CHECK (unhex(sha1) IS NOT NULL AND lower(sha1) = sha1),
 	PRIMARY KEY (sha1)
 ) STRICT;