Database Administrator

1. Modify the DBSNMP password: To reconfigure the DBCONSOLE, you need to enter the DBSNMP password, but any password will display an error and must be modified in advance. SQL> alter user dbsnmp identified by xxx; 2. delete users created on the

Flashback version query is not a new feature of Oracle, but the 10g and 11g functions are enhanced on the basis of 9i, which may be used in some occasions. The following example shows his concept;   ConnectedToOracleDatabase11g

I finally ran my first Java MongoDB operation example. I don't know why MongoDB will always be locked every time I start the machine. I need to delete the lock file to start it, is it related to your own Windows 7 system? Puzzling! PackageMongodb;

I learned a few commands when I got in touch with Oracle and changed the password of the system user. After a few days, I forgot + _ + .. The following describes how to unlock the system user and restore the password. 1. First, use the sys user to

1. spring manages hiberante transactions. When setting the cut plane, you must consider all the places that may involve transactions. Otherwise, the cut plane does not involve any database operations, which occupy a lot of resources and cannot be

HBase is built based on Google's BigTable and is a column-orientednosql database.1. Model View 1.1 concept View From the conceptual model perspective, HBase's storage logic is similar to that of relational databases and is based on Table storage.

1. create user groups and users 1) Add a user group: Groupadd oinstall Groupadd dba 2) Add a user: Useradd-g oinstall-G dba-d/home/Oracle-m oracle {-G indicates the user group,-G indicates the user's additional group,-d indicates the user's main

1 table_exists_action parameter description When using imp for data import, if the table already exists, drop the table before importing. When you use impdp to import a database, if the table already exists, there are four processing methods: 1)

After the database is created, it is not in archive mode by default. To use RMAN for hot backup, you need to manually switch the database to archive mode. Generally, switching the archive mode is performed when the database is in the mount exclusive

Brief Analysis of Oracle data instance recovery When the database crashes suddenly, such as a sudden power failure or hardware failure, the dirty data blocks in the buffer cache are not written into the data file, and the instance crashes, the

Percona provides the query_response_time_stats parameter to observe the database Response Time on the server side.Root @ test 02:29:35> show variables like 'query _ response_time_stats '; + --------------------------- + ------- + | Variable_name |

MyISAM is the default storage engine for MySQL. Each table supports a maximum of _ 4.295E + 09 records and 64 index fields. The two may be larger for different versions. MyISAM also supports full-Text indexing of Text/Blo fields. The tables and

User settingsUlimit-SHn 65535Mkdir-p/home/mysql/infobright/Usr/sbin/groupadd mysql/Usr/sbin/useradd-g mysqlCd/usr/local/soft/Download and decompress64-bit SystemWget http://www.infobright.org/downloads/ice/infobright-3.3.1-x86_64-ice.tar.gzTar zxvf

System: CentOS 5.5 View Log:[Root @ localhost mongo] # tail-20/usr/local/mongo/mongodb. log Mon Sep 19 06:14:55 [initandlisten] MongoDB starting: pid = 4126 port = 27017 dbpath =/usr/local/mongo/data 64-bit Mon Sep 19 06:14:55 [initandlisten] db

Before performing data operations, you must first have several Complete tables. Create two tables, tableA and tableB Create table tableA (id integer, name varchar (25), age number );Insert into tableA values ('20170101', 'jack', '25 ');Insert into

My colleague called and told me that the CPU usage of the database is too high and swap is frequently exchanged. I 'd like to take a look at it now. Here, I will record the entire process for your reference and let you provide some comments. $ Topas

Set OperationsUsed to merge results of multiple select statements Union deduplicationUnion all unionIntersect IntersectionMinus difference set UnionMerge set A and Set B, but remove the duplicate parts of the Two Sets and sort them.SCOTT @ ora10g>

Oracle 10 Gb provides two activation methods, one for users and the other for tables. Implementation Method for users: DBMS_STATS.ALTER_SCHEMA_TABLE_MONITORING ( Ownname VARCHAR2DEFAULT NULL, Monitoring BOOLEANDEFAULT TRUE); How to implement a

For example, an Oracle database has two users: A corresponds to tablespace A and B Corresponds to tablespace B.1. First Use A to export dmp;2. Grant DBA permissions to B and then execute: revoke unlimited tablespace from B;3. alter user B quota 0 on;

The following describes how to install the MySQL database: 1. The master and slave servers perform the following operations respectively::1.1 consistent version1.2 initialize the table and start mysql in the background1.3 modify the root password2.