// LoadBPlusTree 通过BootUUID读取一课B+树, 并返回它.
func Load(bootUUID utils.UUID, dm dm.DataManager) (BPlusTree, error) {
bootDataitem, ok, err := dm.Read(bootUUID)
if err != nil {
return nil, err
}
utils.Assert(ok == true)
return &bPlusTree{
bootUUID: bootUUID,
DM: dm,
bootDataitem: bootDataitem,
}, nil
}
func (e *executor) execute2(stat interface{}) ([]byte, error) {
var err error
tmpTransaction := false
if e.xid == 0 { // 创建一个临时事务
tmpTransaction = true
e.xid, _ = e.tbm.Begin(new(statement.Begin))
}
defer func() {
if tmpTransaction == true { // 结束这个临时事务
if err != nil {
e.tbm.Abort(e.xid)
} else {
_, err = e.tbm.Commit(e.xid)
utils.Assert(err == nil)
}
e.xid = 0
}
}()
var result []byte
switch st := stat.(type) {
case *statement.Show:
result = e.tbm.Show(e.xid)
case *statement.Create:
result, err = e.tbm.Create(e.xid, st)
case *statement.Read:
result, err = e.tbm.Read(e.xid, st)
case *statement.Insert:
result, err = e.tbm.Insert(e.xid, st)
case *statement.Delete:
result, err = e.tbm.Delete(e.xid, st)
case *statement.Update:
result, err = e.tbm.Update(e.xid, st)
}
return result, err
}