makedb: add cache table

makedb.ml

@@ -1,7 +1,8 @@
 (** Init script for the SQLite database. **)
 let inits = "\
 	DROP TABLE IF EXISTS elements; \
-	CREATE TABLE elements (\
+	DROP TABLE IF EXISTS cache; \
+	CREATE TABLE elements ( \
 		num INTEGER PRIMARY KEY NOT NULL, \
 		symb TEXT UNIQUE NOT NULL, \
 		name TEXT UNIQUE NOT NULL, mass FLOAT, \
@@ -10,6 +11,9 @@ let inits = "\
 		oxidation TEXT, state TEXT, \
 		melting FLOAT, boiling FLOAT, density FLOAT, \
 		block TEXT, discovered INTEGER) WITHOUT ROWID; \
+	CREATE TABLE cache ( \
+		name TEXT PRIMARY KEY NOT NULL, \
+		dat BLOB NOT NULL) WITHOUT ROWID; \
 "
 
 (** Converts the column data in the PubChem JSON file to