Database Administrator

Introduction to PostgreSQL user roles and their attributes 1. Users created by create role do not carry the LOGIN attribute by default, while users created by create user have the LOGIN attribute by default, as shown below: Postgres= # Create role

Simple configuration of ASM Environment DescriptionSystem: Red Hat Enterprise Linux Server release 5.4 (Tikanga) Database Version: Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 add Disk Add three hard disks for the ASM disk group: It is

[Oracle] v $ process First, check which columns exist in v $ process SYS @ ORCL> desc v $ process Name Null? Type ----------------------------------------------------------------------------- Addr raw (4) PID NUMBER SPID VARCHAR2 (12) USERNAME

Oracle flashback flash back topic 1. Introduction to flashback:Flashback is used at the following frequency:1> flashback query records that are flashed back to the table for data table record recovery;2> falshabck Table flashback data Table;3>

Oracle merge into syntax 1. Usage of merge:Merge into is a new syntax added by Oracle 9i. It is supplemented at 10 Gbit/s to merge update and INSERT statements and perform join queries with another table based on one table or subquery, match the

How to obtain the Oracle DBID 1. query v $ database to obtain Because DBID has records in the control file and data file, you can query the v $ database view if you can mount the database. SQL> alter database mount; Database altered. SQL> select

Install MySQL 5.5 in Linux source code This article describes how to install mysql5.5 in the source code. The system used is CentOS6.5. 1. Install the corresponding development environmentYum install-y ncurses-develYum install-y libaioYum install-y

Modify the RAC address in Oracle 10 GB This test is based on Oracle 10.2.0.5 SQL * Plus: Release 10.2.0.5.0-Production on Tue Jul 29 20:45:16 2014 Copyright (c) 1982,201 0, Oracle. All Rights Reserved. Connected:Oracle Database 10g Enterprise

Generate DEM using big data in AcGIS When DEM is generated in ArcGIS, the data sources used are usually some height points and contour lines. These height points and contour lines are dense and may contain tens of millions or even hundreds of

Mysql & IFNULL, NULLIF, ISNULL, mysql download I recently used some functions in mysql, some of which were also the first time I encountered, So I recorded them as follows: 1. isnull (expr)Usage: If expr is null, the return value of isnull () is 1;

FAQs about Oracle Installation-1, oracle-1 Installing Oracle may be a simple task for some people, but the installation process contains a wealth of knowledge points, especially on the Linux platform, we may encounter a variety of strange problems.

ORM tool: nhibsmith (2) use CodeSmith to quickly generate ing files and ing classes. ormcodesmith In the previous article "ORM tool: nhib.pdf (1)", we gave a brief introduction to nhib.pdf. The next series of articles will share with you the initial

ADO.net 2-database connection successful --- ShinePans,Database Configuration:Connection string: server = Pan Shang \ SQLEXPRESS; database = db_test; Trusted_Connection = trueConnection code: Using System; using System. collections. generic; using

Restricted query and sorting display (Chapter Summary), Chapter Summary1. Standard data query syntax.SELECT [DISTINCT] * | column [AS] [alias], column [AS] [alias],...FROM table name [alias][WHERE condition (s)][Order by sorting field [ASC | DESC] [,

[Oracle] pl/SQL, oracleplsql This SQL statement can be used to query records at specific locations in a table.   -- Query Method: select * from (select t1. *, rownum rn from (select * from books) t1 where rownum 2; -- Use paging write Stored

Why MySql transactions cannot be rolled back When using MySQL, if you find that the transaction cannot be rolled back, but the Hibernate, Spring, JDBC and other configurations do not have obvious problems, don't worry, first check whether the table

How to check the consistency and consistency of the two tables at the database levelIn general, how can we check whether the content of the two tables is consistent? such requirements are mostly reflected on the slave machine to ensure data

Export an empty table at oracle11g and at oracle11gDeferred_segment_creation Parameter This parameter indicates whether to create a segment immediately when an object (such as a table) is created without data at the beginning. The default value is

Update updates across tables, update updates across tables Sometimes we may need to update data between multiple tables. We can use this statement UPDATE table1,table2 SET table1.column=table2.column, table1.column1=table2.column1WHERE

Oracle tablespace and sqlplus, oraclesqlplus1. Concept of tablespace I have never heard of the table space term in databases that I have used before. When I saw the Oracle database some time ago, I found that the table space is everywhere. Therefore,