no rows selected scott@DB01> select rownum,demono,ename,sal from demo where rownum>3; no rows selected 如果我们想要查询结果集中的某一段范围的记录,比如5-10条的记录,该如何查询呢?很多开发人员把这样的需求称为分页 scott@DB01> select rownum,demono,ename,sal from demo where rownum between 5 and...
select tab.owner,tab.table_name,tab.blocks,tab.num_rows,ind.index_name,ind.clustering_factor, round(nvl(ind.clustering_factor,1)/decode(tab.num_rows,0,1,tab.num_rows),3)*100||'%' "集群因子接近行数" from dba_tables tab, dba_indexes ind where tab.table_name=ind.table_name and tab...
chain_cnt :Number of rows in the table that are chained from one data block to another or that have migrated to a new block, requiring a link to preserve the old rowid. This column is updated only after you analyze the table. 数据缓冲区命中率(百分比小于90就要加大db_cache_size) 查询V$S...
0,1,tab.num_rows),3)*100||'%'"集群因子接近行数"fromdba_tables tab, dba_indexes indwheretab.table_name=ind.table_nameandtab.ownernotin('SYS','SYSTEM','WMSYS','DBSNMP','CTXSYS','XDB','ORDDATA','SYSMAN','CATALOG',
To view the Installation OBE, in your browser, enter the following URL: http://www.oracle.com/webfolder/technetwork/tutorials/obe/db/ 11g/r2/2day_dba/install/install.htm 2-22 Oracle Database 2 Day DBA 3 3 Getting Started with Database Administration This chapter provides a brief roadmap ...
dbOpen--Open a database connection. dbClose--Close a database connection. dbQuery--Execute a query. dbCloseQuery--Close the cursor for a query. dbNextRow--Process the rows of a result set. dbExecute--Execute any SQL statement (DML or DDL). ...
Oracle Database is a relational database management system developed by Oracle. Connect to on-premise Oracle Database to perform various actions such as create, update, get, and delete on rows in a table.This connector is available in the following products and regions:...
DB_ora_29349.trc中出现 *** SESSION ID:(5057.12807) 2016-10-26 14:45:52.726 1. 通过表V$ACTIVE_SESSION_HISTORY来查 查询上面的machine的IP 通过上面的spid在oracle服务器上执行netstat -anp |grep spid即可 出现两个,说明来自220,连接了228数据库服务器,但是又通过228服务器的dblink去连接了16服务器 ...
Gathering object statistic in Oracle is important. The optimizer needs metadata about the object, such as the amount of rows and number of distinct values in a column, to help it decide the optimum way to access your data. This takes effort, and takes place automatically in scheduled windows...
whereround(del_lf_rows/decode(lf_rows,0,1,lf_rows)*100,0)>30; 集群因子clustering_factor高的表 集群因子越接近块数越好,接近行数则说明索引列的列值相等的行分布极度散列,可能不走索引扫描而走全表扫描 代码语言:javascript 复制 select tab.table_name,tab.blocks,tab.num_rows,ind.index_name,ind.cl...