data purging strategy

the data in the temporary table disappears. Also, in the case of multi-user operation, one session never blocks another session using a temporary table. Even if you lock a temporary table, a session does not block other sessions from using temporary tables.A Transaction Temp table is a transaction-related, data in a temporary table that is truncated by itself when a transaction is committed or a transactio

Some time ago, Baidu webmaster platform published a message saying that the majority of webmaster friends can easily ignore some data that users actively access. In fact, the author believes that this is a signal from Baidu side to the majority of webmasters, that is, to tell webmasters that they should pay more attention to brand promotion so that users can know the content of your website services, this will increase the second access traffic of use

Enumeration (enum) type, you can define up to 65535 different strings to choose from, and you can only and must select one of them, which occupies a storage space of one or two bytes, determined by the number of enumerated values; the collection (set) type, which can have up to 64 members, You can select 0 of them to an unqualified number, and occupy a storage space of one to eight bytes, determined by the number of possible members of the collection. For example, in SQL Server, you can save

types Enumeration (enum) type, you can define up to 65535 different strings to choose from, and you can only and must select one of them, which occupies a storage space of one or two bytes, determined by the number of enumerated values; the collection (set) type, which can have up to 64 members, You can select 0 of them to an unqualified number, and occupy a storage space of one to eight bytes, determined by the number of possible members of the collection. For example, in SQL Server, you can

, which can have up to 64 members, You can select 0 of them to an unqualified number, and occupy a storage space of one to eight bytes, determined by the number of possible members of the collection. For example, in SQL Server, you can save a bit type to represent gender (male/female), but MySQL has no bit, with Tintint? No, you can use enum (' Handsome Boy ', ' Meimei ')! There are only two options, so just a byte--as big as tinyint, but it can be accessed directly with the string ' handsome '

$ORACLE _home/bin/rman target/1>> $LOGFILE run{Allocate channel C1 device type disk;Allocate channel C2 device type disk;Allocate channel C3 device type disk;Allocate channel C4 device type disk;Crosscheck backup;Backup as Compressed backupsetIncremental level $BAK _level tag ' ${oracle_sid}_lev_$bak_level 'Database include current controlfile format ' Dump_dir/${oracle_sid}_%u_%t.bak ';Release channel C1;Release channel C2;Release channel C3;Release channel C4;SQL ' alter system archive log cur