Oracle

Two common oracle index B * tree indexesThe bottom layer of a tree is called a leaf node, which contains each index key and a rowid. The indexed leaf nodes constitute a two-way linked list. Once you find that you want to "start" from the leaf node,

Oracle-VPD: Oracle permission control adopts the dbms_rls package of oracle to implement data access control in most systems, permission control is mainly defined as the control of the module's access permissions and the control of the access

Change the ORACLE archiving path and archive mode in ORACLE10g and 11g versions. The default log archiving path in ORACLE is the flash recovery zone ($ ORACLE_BASE/flash_recovery_area ). ORACLE has a limit on this path, that is, it only has 2 GB

Oracle autotrace enabling and option description platform: ora 10g, the RHEL-5.8 steps are as follows: 1) sys @ ORCL> @ $ ORACLE_HOME/sqlplus/admin/plustrce. SQL www.2cto.com 2) sys @ ORCL> grant plustrace to public; Description of several common

Oracle SQL Summary 1: Set functions and multi-table queries 1. Set functions summary 1.1 The where clause cannot use a set function. If you need to use a set function in a judgment statement, use having clause. 1.2 set functions, except COUNT,

Oracle (3) pl/SQL programming basic stored procedures, functions, packages, triggers PLSQL programming (1) 1. Procedures, functions, and triggers are compiled by pl/SQL. 2. Procedures and function triggers are in oracle. 3. pl/SQL is a very powerful

Undo series learning: a simple introduction to transaction slots an oracle data block header has a transaction slot (ITL ). When multiple transaction slots modify data blocks at the same time, and pctfree (proportion of free space of data blocks) is

Rman configuration parameters: [SQL] RMAN> show all; CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 7 DAYS; CONFIGURE BACKUP OPTIMIZATION OFF; # default configure default device type to disk; # default configure controlfile autobackup off; #

In oracle, the time used by commit is not affected by the transaction size. The overhead of commit has two factors: the round-trip communication with the database. If each record is submitted, the generated round-trip traffic will be much larger.

Brief Analysis of the Impact of prompt about Password Expiration when a user's password is about to expire, Oracle will prompt ORA-28002 error at login, but does not affect normal login. I didn't think this information would have a big impact, but I

Description of group functions in oracle: This article introduces considerations for count, sum, avg, max, and min 1. count does not calculate null values www.2cto.com 2, and single row functions (coalesce, nvl, to_char, to_date) is different. The

Subquery: if another query is included in a subquery, The subquery format is SELECT {DISTINCT} * | column name 1 alias 1, column name 2 alias 2, FROM table name 1 alias 1, table name 2 alias 2, (SELECT {DISTINCT} * | column name 1 alias 1, column

When the data on the server is imported to the local database, garbled characters appear, mainly because the character set on the server does not match the local character set.Solution:The imported database is SIMPLIFIED CHINESE_CHINA.ZHS16GBK. The

Oracle note (3) Scott's table structure is being studied in Oracle, focusing on SQL statements, and all SQL statements must be completed under scott, this user has a total of four tables. You can use: SELECT * FROM tab; to view the names of all data

Oracle splits and merges table data in daily database operations. Let's take a look at how to implement it.Assume that the table TEMP_TABLE (ID, NAME, CODE) has the following data: [SQL] select t. * from temp_table t; id name code www.2cto.com 1 A 10

In Oracle, the like method is replaced. The database stores a large amount of data, and the like method is used for queries, which slows down significantly. When I was working on a project, I found that I could use the instr function to replace the

Recovery notes for oracle data tables and data rows: SQL code create table temp_update_doc (docId varchar2 (60) not null, num varchar2 (16) not null) SELECT * FROM esns. temp_update_doc alter table esns. temp_update_doc drop (num); delete from esns.

Oracle 11g table smart monthly partition before the log table more than 7 million data, involved in the log table business query speed is very slow, a month of data query is about 30 seconds, the study found that oracle has a table Partition

You can add or subtract oracle date from DATE or timestamp. The current date can be added to the year, month, day, hour, minute, second, operation of different time types, there are three methods: www.2cto.com 1 using the built-in function

Oracle automatically inserts million rows of records 1. Open the ql/SQL test window www.2cto.com2. input the script -- Created on 2012/11/7 by JERRY declare -- Local variables here count integer; begin -- Test statements here dbms_output.put_line