use savepoints instead of transactions

1 files changed, 17 insertions, 3 deletions

diff --git a/src/guff/database.cr b/src/guff/database.cr
index 9201a38..220c7ef 100644
--- a/src/guff/database.cr
+++ b/src/guff/database.cr
@@ -19,11 +19,13 @@ module Guff
 
     def initialize(path)
       super(path)
+      @savepoint_id = 0_i64
       query(SQL[:pragma_foreign_keys])
     end
 
     def initialize(path, &block)
       super(path)
+      @savepoint_id = 0_i64
       query(SQL[:pragma_foreign_keys])
 
       begin
@@ -123,16 +125,28 @@ module Guff
     end
 
     def transaction(&block)
+      # get next savepoint id
+      id = next_savepoint_id
+
       begin
-        query("BEGIN")
+        query("SAVEPOINT %s" % [id])
         block.call
-        query("COMMIT")
       rescue e
-        query("ROLLBACK")
+        query("ROLLBACK TO %s" % [id])
         raise e
+      ensure
+        query("RELEASE %s" % [id])
       end
     end
 
+    private def next_savepoint_id : String
+      # increment savepoint counter
+      @savepoint_id += 1
+
+      # return savepoint id
+      "guff_savepoint_%s" % [@savepoint_id]
+    end
+
     private def run(
       sql     : String,
       args    : Hash(String, String),