????WAL ( Write-Ahead Logging  ?д??????? ) ??
????3.7.0?汾??SQLite?????????μ?????????????????д???????????????????????????????????????ζ????? web???????κβ?????????????????????????????????????????????????????????д??????????????????? WAL ???????д????????????????????????????д????????????????????????
???????????????????????????????????????????????????????????????????????????????????д????????????????????????????????????????????????????????
????Journal mode = “delete” (the default):
????Writer: BEGIN EXCLUSIVE
????Reader: BEGIN
????Reader: SELECT * FROM foo; Error: database is locked
????Journal mode = “wal”:
????Writer: BEGIN EXCLUSIVE
????Reader: BEGIN
????Reader: SELECT * FROM foo; Returns table contents
????????????????????????????WAL????д???????????????????????????????????????????????з???????????к?????????д??
????????????BerkeleyDB
????BerkeleyDB??SQLite?????????????????????????????????ó????????????????????????BerkeleyDB???????????????????????????????????檔?????BerkeleyDB???????????????и?????????????????????????????????BerkeleyDB??????汾?????????MVCC??????????????????????????????????д??????????????
????BerkeleyDB??????????Ч??????????仰???BerkeleyDB????????????????????и?????????á????????????????????????????????????????
????BerkeleyDB??SQL?????SQLite???????????滻???????????????APIs??????BerkeleyDB?????Щ???????????縴???SQLite?б?????ù?????????????????????BDB????????????????а???BerkeleyDB???????е?????
????BerkeleyDB????????????????????????????У????????????????С???????С?????????????????????????????????????——??????????BerkeleyDB????????????Oracle???????檔
??????????????BerkeleyDB????Python SQLite????????????????????????????
??????????
???????????????????SQLite ?????????FUD??Fear??Uncertainty??Doubt?????????????????Σ???????????????????????????????????web???????á?