Database Administrator

SQL Optimization-logical Optimization-non-SPJ optimization, sqlspj 1) group by group Conversion(Not supported by MySQL) ① Move group operations down The GROUPBY operation may greatly reduce the number of relational tuples. If you can group a

Oracle Spool command and oracleSpool command Run the spool command to copy the output results of SQL * plus to a specified file or query the results. Send to the printer and use the spool off command until it is executed.The spool command syntax

SQL -- process the accumulation of rows, and SQL process the accumulation Background: There is now a report, where the above data is the seller's order data, according to the daily statistics, from the order table to find a seller's order volume

Redis database of 03_NoSQL Database: list type, 03_nosqlredisZookeeper Lists type and Operation List is a linked List structure. The main function room is push, pop, get all values in a range, etc. In the operation, the key is interpreted as the

Oracle quickly creates DBLink SQL statements, oracledblinksql Original Works are from the blog of "Deep Blue blog". You are welcome to reprint them. Please note the following source when reprinting them. Otherwise, you will be held legally liable

Oracle get command and Oracleget commandOracle can use the get command to read file content to the buffer zone,The get command syntax is as follows:Get [file] file_name {list | nolist]File_name indicates an external file, which is included in the

Install mysql in linux and mysql in linux 1. Download mysql. Here I advocate binary installation. Use winSCP to transmit the downloaded mysql to the linux Server 2. decompress the downloaded mysql package #tar -zxvf /{MySQL5.6_path}/mysql-{version}.

Hive exception: UDFArgumentTypeException No argument is expected, argumentexpected Background: Run hivesql in a market today. SQL is normal and there is no problem in data warehouse execution. However, after running in a market, the system always

Oracle express edition 11g cannot open 127.0.0.1: 8080, 11g127. 0.0.1 I installed oracle express edition 11g for oracle learning today, but after the installation is complete, I cannot open the Database Home Page: 127.0.0.1: 8080, baidu. How long

Oracle modifies the listening port number 1521, oracle1521 In oracle, the default listening port number is 1521. Once someone scans this port number, it will know that this server is an oracle database server. This poses an extremely high security

Use mysql workbench to generate the ergraph and workbencher Download and install mysql workbench Drawing In vain Download and install mysql workbench First, download mysql workbench. I use ubuntu 14.04LTS for my own

Oracle 10g Lsnrctl does not reflect the inability to connect to the database, oraclelsnrctlSymptom Description: The oracle version used is 10.2.0.1.0 in linux. If lsnrctl status is entered on the command line interface, no response is returned. If

Java. SQL. SQLException: Can not issue data manipulation statements with executeQuery (), executequery 1. Error description Java. SQL. SQLException: Can not issue data manipulation statements with executeQuery () 2. Error cause Class.

10046 Getting Started: Use 10046 to view the execution plan and read the trace file, 10046 trace **************************************** * ********************* 1. enable 10046 ************************************** * ********************* SQL>

PL/SQL if statement execution sequence, plsqlif statement The if statement Syntax of PL/SQL is defined as follows: IF condition THEN {... Statements ...} ELSIF condition THEN {... Statements ...} ELSE {... Statements ...} End if; Since PL/SQL is

Redis cluster _ 1. redis master-slave configuration, redis cluster _ 1. redisMaster-Slave Redis configuration (Master-Slave)I. Redis Replication features:1): one Master can synchronize multiple Slave instances.2): not only can the Master synchronize

Hpux mcsg oracle 10.2.0.4 rac for storage image, hpuxmcsgA recent case:Status quo: hp-ux operating system, oracle 10.2.0.4 rac, mcsg mode, two ocr and three voting disks correspond to one lv in the same concurrent volume group.Objective: To create

ERTU. The database model starts from here and er starts here. Today, Zibin's senior brother asked me to design a database table for the project first. I 'd better draw an erfigure. ERTU: I know what it is, because I used to take database and

Scrolling result setA scrollable result set means that when reading records in the database, we do not need to read the records one by one. Instead, we can skip several records based on our specific needs before reading the results.The two

Use of packages in OracleUse in Oracle The main purpose of using a package is to modularize the program. The package can combine the relevant stored procedures, functions, variables, constants, cursors, and other PL/SQL programs, in this way, code