Oracle

Oracle Star Schema analysis Star conversion is a very powerful optimization technology, which is implemented by implicit rewriting of the original SQL statement, it can greatly reduce I/O. end users do not need to know any details about star

Oracle Creates table partitions based on existing tables and data and imports data. Assume that the existing System. Test Table has over 10 million data records and is in the ts_Test tablespace. The table contains column A, which partitions data

Outline of common Oracle listener Operation Manual: www.2cto.com [SQL] LSNRCTL> help The following operations are available An asterisk (*) denotes a modifier or extended command: start stop status services version reload save_config trace spawn

Oracle foreign key constraint operations disable all foreign key constraints www.2cto.com select 'alter table' | table_name | 'Disable constraint' | constraint_name | '; 'From user_constraints where constraint_type = 'R'; enable all foreign key

Three States of oracle redo log group: current, active, inactive current: indicates that the log group is the current log group, oracle is using this log group; active: when the current redo group switches logs, the status changes to active.In

In the REL5 oracle service shell, create an oracle file in/etc/init. d/. How can I get the Java code www.2cto.com #! /Bin/sh # oracle service start or stop shell ORA_HOME =/home/oracle/db/oracle/product/12.1.0/db_1 ORA_OWNER = oracle if [! -F $

The Oracle view user_tab_modifications collects the dml operation data of the table that has been changed since the collection information. A table is periodically collected only when the data volume is changed by more than 10%, you can also execute

In oracle, check the week number of the system. The week number of the year is www.2cto.com select to_char (sysdate, 'ww '), to_char (sysdate, 'iw ') from dual; select to_char (sysdate, 'ddd ') from dual; select TRUNC (SYSDATE, 'mm') from dual; 1)

When creating a unique constraint, the OCP will forcibly create or reuse the index www.2cto.com (if no index exists in the previous column, the created index is a unique index. In this case, the index name and the constraint name are the same, and

OCP question analysis _ 043: buffer cache and hit rate calculation method: www.2cto.com SELECT name, (1-(physical_reads/(db_block_gets + consistent_gets) * 100 H_RATIO FROM v $ ratio; the hit rate, as the standard for measuring the performance of

Oracle login times ORA-28000: the account is locked-Error 1, found problems using PL/SQL Developer login scott user input user name and password, reportedORA-28000: the account is locked-solution error. Www.2cto.com 2. solution 1 use an

1. Download the oracle Instant Client (note: this is not a sqlplus customerEnd) http://www.oracle.com/technetwork/database/features/instant-client/index-097480.html. My local host is window7, so I chose to download the Instant Client for Microsoft

Oracle (2) DDL statement create, alert, drop, truncate II. data Definition (DDL) Section www.2cto.com 1. CREATE (create table, index, view, synonym, process, function, database link, etc.) Common ORACLE field types include CHAR fixed length string

Estimate the index size (dbms_space.create_index_cost) before creating an index for a field in a table. The best way is to create an index in the test database for prediction.If no test environment is available, you can use

Oracle uses sqlplus to query a table space according to the condition. Everyone knows that oracle queries the table space according to the condition, but the query time of the table space seems to be a bit different from that of www.2cto.com: 1

In-depth introduction to oracle locks-principles: in modern multi-user multi-task systems, multiple users may access a shared object at the same time. This object may be a table, row, or memory structure, to solve the data security, integrity, and

Cainiao oracle -- ORA-28000: the account is locked solution 1. today, oracle 10g and plsql are installed, and an error is reported when scott is installed. the reason is: scott of Oracle10g cannot log on 3 by default. solution: 1: www.2cto.com Step 1

Example 1 of Oracle high water level line shrinking. background We know this situation. In oracle, assume that table A originally had rows of data, and then deleted rows of data, leaving only rows of data, the time for full table scan to Table A has

In oracle connection, in addition to returning rows that meet the connection conditions, the two [SQL] tables return rows that do not meet the conditions in the left (or right) table, this connection is called a left (right) Outer Join. In addition

Oracle single-row and multi-row function instancesSingle-row and multi-row functions:Single-row functions can be divided into five types: character functions, numeric functions, date functions, conversion functions, and general functions.Single Row