sqlite: quick exec with result (#361)

eth/db/kvstore_sqlite3.nim

@@ -226,6 +226,16 @@ proc exec*[Params: tuple](db: SqStoreRef,
   if finalizeStatus != SQLITE_OK and result.isOk:
     return err($sqlite3_errstr(finalizeStatus))
 
+proc exec*[Params: tuple, Res](db: SqStoreRef,
+                              stmt: string,
+                              params: Params,
+                              onData: ResultHandler[Res]): KvResult[bool] =
+  let stmt = ? db.prepareStmt(stmt, Params, Res, managed = false)
+  result = exec(stmt, params, onData)
+  let finalizeStatus = sqlite3_finalize(RawStmtPtr stmt)
+  if finalizeStatus != SQLITE_OK and result.isOk:
+    return err($sqlite3_errstr(finalizeStatus))
+
 template exec*(db: SqStoreRef, stmt: string): KvResult[void] =
   exec(db, stmt, ())
 

tests/db/test_kvstore_sqlite3.nim

@@ -52,6 +52,15 @@ procSuite "SqStoreRef":
       countRes.isOk and countRes.get == true
       totalRecords == 3
 
+    # Without prepare..
+    totalRecords = 0
+    check:
+      (db.exec("SELECT COUNT(*) FROM records;", ()) do (res: int64):
+        totalRecords = int res).get()
+
+    check:
+      totalRecords == 3
+
     let selectRangeStmt = db.prepareStmt(
       "SELECT value FROM records WHERE key >= ? and key < ?;",
       (int64, int64), openarray[byte]).get