MySQL? Wait_Timeout ??? ???? ?? ??? ??????
thewait_timeoutvariableinmysqlspecififieshowlongeserverThreadwaitsforactivitivityOnanon-interactiveConnectionbeforeclosingit; whenAconnectionRemainsIdLelongerThanthisValue, mysqlterminatesIttOfReEresources
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SQL? ?? ???? ???? ?? ????????
USETEMPORARYTABLESTOBREAKDOWNCOMPLEQUERIES? InterMETERMETERSULTSFORCLARITY ? FORMENTONCENTORMETERINGSTORMENTIONSTROCEDURESORESORDUCHINGEDUNDANTI/OONLARGETABLES? ???? repeatEdOperationsOnePeatEdOperationsOnePeatEdOperationsOndErmeTeRforferMance.3
Aug 05, 2025 pm 12:44 PM
MySQL ???? ?? ?? ? ?? ?? ??
MySQL ?? ??? ????? ??? ??? ??, ???? ?? ?? ? ???? ? ?? ??? ???????. 1. ??? ?? ?? : ? ???? ?? ?? ? ?? ???? ???? ? ??? ???? ??? (?? 20%-30%), Undolog, Redolog ?? ?? ?? ??? ??????. 2. ???? ?? ?? : ?? ??? ????? ???? ?? ??? ????? ??? InnoDB? ?????. ?? ??? ????? ??? ?? ??? ?? ? ? ????. ?? ??? ?? ??? ?? UTF8MB4 ?? UTF8/LATIN1? ??????. 3. ?? ???? ? ?? : ??? ?? ? ??? ??? ????? ???? ?? ?? ?? ???? ??? ???? ???????? ???? ?? ? ? ??? ????? ?? ??? ???? ???? ??? ?? ? ? ????.
Aug 05, 2025 pm 12:33 PM
?? ????? Oracle SQL Trace ? TKPROF
sqltrace? ????? ??? 1. ?? ?? ??? : AltersessionSetsetSql_trace = true ??; 2. ?? ?? ??? : dbms_session.set_sql_trace_for_session? ?? Sid ? Serial_num? ?????. 3. ??? ??? : ??? ?? ?? ??? ???? sql_trace = true? ????? ????? ????. ?? ? ??? ?????. TKPROF? SQLTrace?? ?? ? ?? ?? ????? ?? ?? ??? ???? ???? ? ?????. tkproftracefile.trcoutput.txt? ?? ???? ??.
Aug 05, 2025 pm 12:01 PM
phpmyadmin?? ???? ???? ??
??, CheckifTetAbleDesrePairBairCecktableYOUR_Table_name; inphpmyAdmin — QTESTATUSISNOT'OK ', thetableIscorRupted.2.TorePair, "DropDown, OrrunePairtable_table_name"?? "?? ???"?? ??? "?? ???"
Aug 05, 2025 am 11:01 AM
SQL ???? ??? ? ???? ??? ??????
??? ???? ??? ?? ?? ?? ???? ???? ?? ??? ?? SQLServer? ???? ???? ?? ??? ?????. ?? ???? ???? ???? (???? ???? ?? I/O? ??) ? ?? ?? (??? ??? ??? ???? ???? ???? ????). ??? ??? 10% ???? ??? ?? 1000? ???? ???? sys.dm_db_index_physical_stats ??? ?? ?? ? ? ????. 1. ??? ??? 10%???? ?? ? ??? ????. 2.10% -30%? ???? ???? ? ?????. 3. AlterIndexRebuild? ???? ??? ???? ? 30% ??? ??? ??? ?? ? ?????. ??
Aug 05, 2025 am 10:49 AM
?? SQL ????? ?? ??? ????? ??????
???? ?? ????? ????? Altertable ?? ??????. 1. altertabletable_nameaddcolumncolumn_namedata_type [Constraints] ?? ?? ? ?? ??? ?? ???? ???? ???? ?? ?? ??????. 2. ?? ??? ? AltertableTable_namedRopcolumncolumn_name ??? ??????. ?? ?? ??? ?? ?????. 2. ?? ??? ? altertabletable_namedRopcolumncolumn_name ??? ??????. ?? ??, ??? ?? ?????.
Aug 05, 2025 am 10:35 AM
????? ???? ??? ???
Oracle ???? ???? ?? ??? ???, ??? ?? ? ?? ??? ????????. 1. CreateOrReplacetrigger? ???? ??? ??? ??????. 2. ???? ???? ?, ? ?? ??? ?????. 3. ??? ??, ???? ?? ??? ?????. 4. ?? ??? ??? ?????. 5. ??? ???? ?? ?? ????? ??????. 6. ??? ??? ???? ???? ??; 7. ??? ? ??? pl/sql ??? ????. ?? ??, ??? ??? ?? ???? ??? ? ??? ?? ???? ??? ??? ???? ????? user_triggers? ?????.
Aug 05, 2025 am 09:54 AM
SQL? ??? ? ??? ??????
??? ? ?? (TVFS) returnAbleAndcomeIntWotypes : ???, whyseSounseLectStatement ? Multi-Statement, whithLugtipleSqloperationStobuildAcustomResultset.2. theyofferesability, Paramerization ? SeamlessIntegrationIntoInsliketa
Aug 05, 2025 am 09:44 AM
MySQL? ???, ?? ? ??? ???? ??????
deletereMovesspecificorAllrows, KeepStableStructure, ?? ?? ??? ? DOSNOTRESETAUTO-Increment; 2.TrUncateQuicklyRemovesAllrows, resetSauto-increment, Most Cases, Disfiretiggers, and KeepstableSthee;
Aug 05, 2025 am 09:39 AM
phpmyadmin?? ??? ??? ???? ??
AccessHerAccountStabinphpmyAdminusinganadminAccounttomanagemySqlusers.2.CreateAwuserByClicking "AddUserAccount", SetingAusername, ???, StrongPassword ? ? AssigningMinimimentMinimimentSaryprivileges.3.EditeSiSersbysElecting "EditPrivile
Aug 05, 2025 am 09:22 AM
SQL? ???? NULL? ??? ????? (? : column = null)?
NULL? ???? ???? ? ??? ???? ??? ?? ??? ??? ?? ??? SQL?? NULL ?? ?? ? ? ?????? ?????. 1. ISNULL? ???? NULL ?? ??????. = NULL? ???? ???? ? ??? ?????. 2. NOTIN? ??? ???????. ?? ??? NULL ?? ?? ? ?? ?? ??? ???? ?? ? ????. ?? ??? ????? ? ??? ???????. 3. COUNT, SUM ? AVG? ?? ?? ??? NULL ?? ???? COUNT (*) COUNT (*)? ?? ?? ???? COUNT (?)? NULL ? ? ?????. ??? ??? ???? ?? ??? ???? ??? ?? ? ????.
Aug 05, 2025 am 08:49 AM
MongoDB ?? ????? ?? ??? ?? ?? ??
?? ??? ???? HongodBdriverseeConnectionStoredUceOverHead, LimitCurrentOperationsViaPoolsize, AndrequireProperManagementToaVoidoutSorResourceExhaustion.2.tuneConnectionPoolsettingsBasedOnWorkloadByConfigurin
Aug 05, 2025 am 08:46 AM
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