Oracle

Oracle db studay first queries the free space select tablespace_name, file_id, block_id, bytes, blocks from dba_free_space; www.2cto.com adds the Oracle tablespace query data file name, size, and path information select tablespace_name, file_id,

Oracle is really difficult to uninstall .... 1. Choose "start"> "Settings"> "Control Panel"> "Administrative Tools"> "services" to stop all Oracle services. 2. Start-> Program-> Oracle-OraHome81-> Oracle Installation Products-> Universal Installer,

Install oracle10g + asm under rhel --- build su-root www.2cto.com mkdir/asmdisk = in unix/linux, all devices are files, so we can create several files to simulate multiple hard disks. Create several files with dd, the size is 1Gdd if =/dev/zero of =/

Oracle Study Notes II football schedule statisticsLink: the internal link, external link, and self-link of SQL, one of the Oracle study notes, is a common SQL problem. Title Description: Team table: team code team name 001 Barcelona 002 Real Madrid 0

Oracle year, quarter, month, week, day, grouping Java code table 1: Date (exportDate) Quantity (amount) -------------- ----------- 14-2 month-08 20-3 month-08 2 14-4 month-08 6-6 month-08 75 24-10 month-09 23-11 month-09 45 04-8 month-10 5 04-9

Oracle batch export Stored Procedure Method 1: PL/SQL tool export Method 2: SQL code SET echo off; SET heading off; SET feedback off; spool C: \ Documents and Settings \ Administrator \ Desktop \ proc. SQL; -- 1. If the sys user is used, use the SQL

Modify the Oracle database character set to UTF8 to view the character set select userenv ('language') from dual; 1. conn/as sysdba 2. run the following code: shutdown immediate; startup mount exclusive; alter system enable restricted session; alter

Oracle result set cache: oracle adjusts the result set cache with only three parameters. RESULT_CACHE_MAX_SIZE = 500 M/* Megabytes RESULT_CACHE_MAX_RESULT = 20/* Percentage limit = 3600/* Minutes, but all queries are saved only when

How to Use UPDATE nowait in oracle 1. UPDATE nowait applies the following scenarios: query a piece of data and enable database transactions for it.If no lock is applied to the current data, the system returns the correct result and locks the current

Brief considerations for Oracle Silent Installation the environment configuration for Silent Installation is the same as that for graphical installation. Here we will not repeat the main points: ① The response files are mainly used in the downloaded

Oracle wm_concat (column) function in Oracle data, use the wm_concat (column) function, you can merge the selected field data values; 1. merge a single field value, for example: SQL: select t. id, t. name, t. price, t. count, t. uid from goods t;

Oracle collects user permissions [Use Cases] preparations before the system goes online. Generally, the dump File Import method is often used for data migration. Because the data is imported by one user, a permission error (which can be ignored) is

ORA-20000: ORU-10027: buffer overflow, limit of 2000 bytes solves the problem of using dbms_output.put_line to output the statement with the following error: begin user_priv (username => 'hr'); end; ORA-20000: ORU-10027: buffer overflow, limit of 200

When updating or deleting a record, the operation cannot be performed, or the lock is fixed. Sometimes, when we perform update or delete on oracle, the operation result cannot be obtained at the previous time,The record is still being processed. At

Oracle's PLSQL single-line functions and group functions are a program with zero or multiple parameters and a return value. Oracle has a series of built-in functions in SQL, which can be called SQL or PL/SQL statements. functions are mainly divided

How to obtain the current system time in Oracle select to_char (sysdate, 'yyyy-mm-dd hh24: mi: ss') from dual; select to_char (sysdate, 'yyyy') from dual; -- select to_char (sysdate, 'mm') in ORACLE ') from dual; -- month select to_char (sysdate,

RMAN performance optimization full strategy (I) It is easy to say that RMAN is doing operations during backup and recovery: Reading data from the "Source" to the buffer zone, then the self-read buffer is written to the "destination", and a lot of

Generally, creating a directory in Oracle is to use a Data Pump to import/export data. In fact, directory has many other functions, this article does not elaborate 1. CREATE [or replace] directory DIRECTORY directory AS 'pathname' syntax for

The oracle expdp command uses detailed parameters and export example: 1. DIRECTORY specifies the DIRECTORY where the dump and log files are located DIRECTORY = directory_object Directory_object is used to specify the DIRECTORY object name. note that

In-depth understanding of the relationship between Oracle tables (4): Tables and segments (segments) in-depth understanding of Oracle tables (3 ): the Connection Methods of the three tables are described as follows: Nested loop join and Sort merge