diff --git a/db/accessor.go b/db/accessor.go
index f3b3e9b..fdb4269 100644
--- a/db/accessor.go
+++ b/db/accessor.go
@@ -9,10 +9,7 @@ type Block struct {
 type DBAccessor interface {
 	IsMigrated() (bool, error)
 	Migrate() error
-	FindLatestBlocks(time int64, limit int) []Block
-
-	//Block range lookup
-	FindBlocks(posx int, posz int, posystart int, posyend int) []Block
-	GetXRange(posystart int, posyend int) (int, int)
-	GetZRange(posystart int, posyend int) (int, int)
+	FindLatestBlocks(mintime int64, limit int) []Block, error
+	FindBlocks(posx int, posz int, posystart int, posyend int) []Block, error
+	CountBlocks(x1, x2, y1, y2, z1, z2 int) int, error
 }
diff --git a/db/sqlite.go b/db/sqlite.go
index dfd46f3..effa90f 100644
--- a/db/sqlite.go
+++ b/db/sqlite.go
@@ -11,22 +11,18 @@ func (db *Sqlite3Accessor) Migrate() error {
 	return nil
 }
 
-func (db *Sqlite3Accessor) FindLatestBlocks(time int64, limit int) []Block {
+func (db *Sqlite3Accessor) FindLatestBlocks(mintime int64, limit int) ([]Block, error) {
 	return make([]Block, 0)
 }
 
-func (db *Sqlite3Accessor) FindBlocks(posx int, posz int, posystart int, posyend int) []Block {
+func (db *Sqlite3Accessor) FindBlocks(posx int, posz int, posystart int, posyend int) ([]Block, error) {
 	return make([]Block, 0)
 }
 
-func (db *Sqlite3Accessor) GetXRange(posystart int, posyend int) (int, int) {
-	return 0, 0
+func (db *Sqlite3Accessor) CountBlocks(x1, x2, y1, y2, z1, z2 int) (int, error) {
+	return 0
 }
 
-func (db *Sqlite3Accessor) GetZRange(posystart int, posyend int) (int, int) {
-	return 0, 0
-}
-
-func NewSqliteAccessor(filename string) {
-
+func NewSqliteAccessor(filename string) (*Sqlite3Accessor, error) {
+	return nil, nil
 }