Oracle

Common Methods for changing rows of Oracle columns 1. Converting rows and columns with fixed columns such as student subject grade --------- ---------- student1 language 80 www.2cto.com student1 mathematics 70 student1 English 60 student2 language 90

Rule 1 for Oracle 10g schema object names) except for the database link name, the schema object name can contain a maximum of 128 characters and a maximum of 30 characters. 2) reserved words (such as SELECT) cannot be used as object names. 3) All

As far as I know, oracle versions 10 Gb later than oracle will not cause deadlocks due to user operation. This problem occurs when you log on to the system using the user name and password on the home page of your web project. You cannot access the

The SQL in statement can be joined up to 1000. By default, Oracle supports 1000 in the number of in statements. This is also for SQL Performance processing, because in statements do not have good performance. In this case, it is best to use

What is the problem when the sequence reaches the maximum value in Oracle? The sequence is a database object provided by oracle to generate a series of unique numbers. The sequence will automatically generate an ascending sequence number, to

Differences between decimal and Number in Oracle 1. DECIMAL Type Details Oracle only supports the decimal type in syntax, but it is actually the number type at the underlying layer, the decimal type is supported to move data from an Oracle database

In Oracle, The String Conversion format of the to_char () function is summarized as follows: to_char (var [, format]) Function Conversion format description: 1. [format] '000000' N indicates the number of numbers in the converted format.If the

How to reconfigure the redo log location 1. shut down database shutdown2. use the OS command to copy redo log files to the new location mv/u01/app/oracle/oradata/MYNEWDB/onlinelog/o1_mf_1_89y70t1b _. log/home/o1_mf_000089y70t1b_test.log3. start the

Commands for setting Oracle archive mode: 1. log on to the database as sysdba 2. archive log list; view database and archive information; 3. Shut down the database normally, such as using shutdown immediate; 4. Start the database by loading. startup

Oracle user-managed backups introduces how to manage backups. the following concepts are described: Full-Database Backup: 1. consistent backup (cold backup), that is, backup after the database is closed, because the data file header and the control

[ORACLE Foundation 1] addition and subtraction of oracle DATE can be performed on both DATE and timestamp. You can add the current date to different time types by year, month, day, hour, minute, and second. There are three methods: 1. Use the

Run DBCA. NETCA reports Xlib: connection to ": 0.0" refused by server error troubleshooting fault symptom: Fault Analysis: From the fault symptom, it is caused by xhost problem, this error usually occurs when you remotely execute the pop-up window.

Oracle optimization query Skills 1. connection sequence in WHERE clause: ORACLE uses the bottom-up sequence to parse the WHERE clause. According to this principle, the connection between tables must be written before other WHERE conditions, the

Oracle wait event-1. Knowledge about waiting events 1. The concept of waiting events from the source is introduced from ORACLE 7.0.12, with approximately 100 waiting events. In ORACLE 8.0, this number has increased to approximately 150, with

Drop database ORA-01504 problems oracle 11g for win2008dc, drop database. c: \ Users \ Administrator> set nls_lang = AMERICAN_AMERICA.ZHS16GBK C: \ Users \ Administrator> sqlplus "/as sysdba" SQL * Plus: release 11.2.0.3.0 Production on Wed May 8 08:

Reasons for slow query speed in Database Analysis: 1. No index or no index is used (this is the most common problem of slow query and is a defect in programming) 2. Low I/O throughput, resulting in a bottleneck effect. 3. the query is not optimized

Common principles of oracle tablespace design principles: 1. Generally, a large table or index is allocated with a single tablespace. 2. The Read only object or Read mostly object is grouped into a group and exists in the corresponding tablespace. 3.

GoldenGate Series 1: quick setup of one-way synchronization GoldenGate environment 1. Environment preparation (1) download the installation package and decompress it to ORACLE_BASE (2) modify the environment change [plain] [oracle @ irms156ogg] $ vi

Use PL/SQL to obtain the statement Create procedure: create or replace procedure created as cursor get_username is select username from dba_users; begin for l_user in get_username loop DBMS_OUTPUT.PUT_LINE ('authorization ('-----------------------');

Oracle is prone to errors. logical comparison of null and ''1. In Varchar2 format,'' is equivalent to null (no memory is allocated ). [SQL] the result of the statement 'aa from dual where ''is null exists in select.2. logical judgment on null is not