sqlite: modify exec functions + other fixes

examples/sqlite.v

@@ -14,7 +14,8 @@ fn main() {
 	name := db.q_string('select name from users where id = 1')
 	assert name == 'Sam'
 	
-	users := db.exec('select * from users')
+	users, code := db.exec('select * from users')
+	println("SQL Result code: $code")
 	for row in users {
 		println(row.vals)
 	}	

vlib/sqlite/sqlite.v

@@ -5,8 +5,8 @@ module sqlite
 #flag freebsd -Wl -L/usr/local/lib -lsqlite3
 #include "sqlite3.h"
 
-struct C.sqlite3
+struct C.sqlite3 {}
-struct C.sqlite3_stmt
+struct C.sqlite3_stmt {}
 
 pub struct DB {
 mut:
@@ -18,12 +18,24 @@ pub mut:
 	vals []string
 }
 
+fn C.sqlite3_column_text(voidptr, int) byteptr
+fn C.sqlite3_column_int(voidptr, int) int
+fn C.sqlite3_open()
+fn C.sqlite3_step() int
+fn C.sqlite3_prepare_v2()
+fn C.sqlite3_finalize()
+fn C.sqlite3_column_count(voidptr) int
+
+// Opens the connection with a database.
 pub fn connect(path string) DB {
 	db := &C.sqlite3(0)
 	C.sqlite3_open(path.str, &db)
-	return DB {conn: db}
+	return DB{
+		conn: db
+	}
 }
 
+// Returns a single cell with value int.
 pub fn (db DB) q_int(query string) int {
 	stmt := &C.sqlite3_stmt(0)
 	C.sqlite3_prepare_v2(db.conn, query.str, -1, &stmt, 0)
@@ -33,14 +45,7 @@ pub fn (db DB) q_int(query string) int {
 	return res
 }
 
-fn C.sqlite3_column_text(voidptr, int) byteptr
+// Returns a single cell with value string.
-fn C.sqlite3_column_int(voidptr, int) int
-fn C.sqlite3_open()
-fn C.sqlite3_step() int
-fn C.sqlite3_prepare_v2()
-fn C.sqlite3_finalize()
-fn C.sqlite3_column_count(voidptr) int
-
 pub fn (db DB) q_string(query string) string {
 	stmt := &C.sqlite3_stmt(0)
 	C.sqlite3_prepare_v2(db.conn, query.str, -1, &stmt, 0)
@@ -51,36 +56,48 @@ pub fn (db DB) q_string(query string) string {
 }
 
 
-pub fn (db DB) exec(query string) []Row {
+// Execute the query on db, return an array of all the results, alongside any result code.
+// Result codes: https://www.sqlite.org/rescode.html
+pub fn (db DB) exec(query string) ([]Row,int) {
 	stmt := &C.sqlite3_stmt(0)
 	C.sqlite3_prepare_v2(db.conn, query.str, -1, &stmt, 0)
 	nr_cols := C.sqlite3_column_count(stmt)
-	//println('nr cols $nr_cols')
+	mut res := 0
 	mut rows := []Row
 	for {
-		ret := C.sqlite3_step(stmt)
+		res = C.sqlite3_step(stmt)
-		if ret != 0x64 {
+		// Result Code SQLITE_ROW; Another row is available 
+		if res != 100 {
 			break
 		}
 		mut row := Row{}
 		for i in 0 .. nr_cols {
 			val := tos_clone(C.sqlite3_column_text(stmt, i))
 			row.vals << val
-			//println(val)
 		}
 		rows << row
 	}
-	return rows
+	return rows,res
 }
 
+// Execute a query, handle error code
+// Return the first row from the resulting table
 pub fn (db DB) exec_one(query string) ?Row {
-	rows := db.exec(query)
+	rows,code := db.exec(query)
+	if rows.len == 0 || code != 101 {
+		return error('SQL Error: Rows #$rows.len Return code $code')
+	}
 	return rows[0]
 }
 
-/*
+// In case you don't expect any result, but still want an error code
+// e.g. INSERT INTO ... VALUES (...)
+pub fn (db DB) exec_none(query string) int {
+	_,code := db.exec(query)
+	return code
+}
+
+/* TODO
 pub fn (db DB) exec_param(query string, param string) []Row {
 }
 */
-
-

vlib/sqlite/sqlite_test.v

@@ -10,14 +10,20 @@ fn test_sqlite() {
 	db.exec("insert into users (name) values ('Kate')")
 	
 	nr_users := db.q_int('select count(*) from users')
-	println('nr users = $nr_users')
+	assert nr_users == 3
 	
 	name := db.q_string('select name from users where id = 1')
 	assert name == 'Sam'
 	
-	users := db.exec('select * from users')
+	users, mut code := db.exec('select * from users')
 	assert users.len == 3
-	for row in users {
+	assert code == 101
-		println(row.vals)
+
+	code = db.exec_none('vacuum')
+	assert code == 101
+
+	user := db.exec_one('select * from users where id = 3') or {
+		panic(err)
 	}
+	assert user.vals.len == 2
 }