Database Administrator

I. Official Website description Http://download.Oracle.com/docs/cd/E11882_01/server.112/e26088/functions088.htm#SQLRF00658 Purpose The LENGTH functionsreturn the length of char. LENGTH calculates length usingcharacters as defined by the input

Oracle connection string reported error ORA-01722: solution to invalid numbers, the following function, used to find a string similar to create or replace function f_GetUsers (key in varchar2, P_cursor out pkg_test.myrctype) Return number is

1. Select the most efficient table name order The SQL parser processes the table names in the FROM clause in the order FROM right to left. If the FROM clause contains multiple tables, you must select a table with the least number of records as the

First look at the table content Select name, pass from t1; 2. Method 1: Use the decode Function Select name, decode (pass, 'passs111', 'pass1', 'pass222', 'pass1', '', 'Password') from t1; Note: If you do not list the possible conditions in the

Count the number of employees in the Department (number of employees = number of employees in the department + number of lower-level departments)Department table: Employee table: SQL statement: With Temp As( SelectT1.deptidAsId, t1.supdeptid

I. date type usage The date type subtraction only obtains the number of days.SQL> SELECT sysdate-(sysdate-1) FROM dual;SYSDATE-(SYSDATE-1)-------------------1Make an experiment:Create table t2 (d1 date, d2 date); -- create a tableInsert into T2

In fact, the main problem is to automatically start the Oracle service. There are also many examples on the Internet, but the success may not be achieved according to the example, next, let's take a look at the issues in the configuration process

This article does not compare Oracle Spatial with ST_Geometry. For details about the comparison, refer to: here, the data structure and performance comparison are clearly described. In fact, this document shows that OracleSpatial in ArcGIS is

Open Database flashback1. Check whether flashback is enabled for a database. There are two simple methods:(1) directly query the databaseSQL> select name, log_mode, flashback_on from v $ database; NAME LOG_MODE FLASHBACK_ON---------------------------

When I was installing OracleXE for developer Demon today, there was a prompt: Destination Folder: D: \ oraclexe \ PortFor 'Oracle Database Listener'1521 PortFor 'Oracle Services for Microsoft Transaction Server'2030 PortForHTTP Listener:

MongoDB usage notes 1. Installation Package http://www.mongodb.org/downloads Ii. server use LINUX version: ① Use tar-zxvfmongodb-linux-x86_64-1.2.4.tgz to decompress the installation package ② Mkdir-p/data/db create directory ③ Cd/data/db go to the

Ubuntu: After installing MongoDB and Python, how does Phython access the MongoDB database?Python is a simple programming language and the developed code is very readable.This article uses the Python driver called PyMongo driver and MongoDB to

Exp_p.sh #! /Bin/sh #$1 generate the storage path of the dmp File If [-d "$1"]; then Echo "" $1 "exist" # The user name/password generated file name is automatically generated based on the date of the day, for example, 20111128.dmp Exp

1: get/load access to a single piece of data Public Teacher getTeacherById (Long id ){ Return (Teacher) this. hibernateTemplate. get (Teacher. class, id ); } Public Teacher getTeacherById (Long id ){ Return (Teacher) this.

Problem description: another small problem today: After adding two new fields to a table, the query speed is obviously slow. We suspect this is caused by row migration. If you try to move it, it will be OK. Impact of row migrationIf you read this

The Oracle user must perform operations on the Oracle server. The procedure is as follows: 1. Retrieve the font file simsun. ttc from windows 2. Create the fallback folder in the $ ORACLE_HOME/jdk/jre/lib/fonts directory. Command: mkdir fallback

Oracle trigger simple table instance Create table dwuser. T1 (OLD_VALUE NUMBER (7,2 ),NEW_VALUE NUMBER (7,2 ),UP_DATE DATE );Create table dwuser. EMP (empno number (4 ),ENAME VARCHAR2 (10 BYTE ),JOB VARCHAR2 (9 BYTE ),Mgr number (4 ),Hiredate

Syntax: REPLACE (char, search_string, replacement_string) Usage: convert all the string search_string in char to the string replacement_string without matching strings. Example: SQL> select REPLACE ('fgsgswsgs ', 'fk', 'J') from dual; return

1. After mysql is installed, the directory distribution in linux is as follows: Database Directory:/var/lib/mysql Configuration File:/usr/share/mysql (mysql. server command and configuration file) Related commands:/usr/bin (commands such as

This command uses a statement to update and insert data to a table from one or more data sources. in Oracle 9i, the UPDATE and INSERT keywords must be specified at the same time. ORACLE 10g has made the following changes.1. insert and update are