Database Administrator

Statement for Oracle row-to-column conversion: /* Drop table foo; */ /** Create a demo table **/ Create table foo ( Bbbid number (2), -- primary key Depid number (2), -- unit NUMBER AAC006 VARCHAR2 (1) -- Gender 1 male 2 female 0 unknown CONSTRAINT

In the previous section, we explained some understanding and concepts of mongodb (see for details). Next, we will step into mongodb learning. Unlike apsaradb for mongodb, which has powerful GUI clients, apsaradb for mongodb also has powerful

To partition the Collection objects stored in the MongoDB database, you need to select the Shard Key. The selection of the Shard key directly determines whether the data distribution in the cluster is balanced and whether the cluster performance is

Background: 1) When we take a disk offline in case the disk is already upted or database is not able to read or write from the disk. in case of Oracle database 10 Gb, oracle engine use to balance the other disks with the content of offline disk.

When the Oracle database is shut down normally, the committed transaction has been written into the data file, and the uncommitted transaction has been rolled back, the data in the control file, log file, and data file is consistent. You do not need

Sometimes, database faults and data loss may inevitably occur in the enterprise due to disk damage. At this time, data backup is particularly important. In this section, we will focus on loading data files,RedoLog File,ControlfileDisk damage data

I. Functions of scn The role of Scn is to ensure Database Consistency. It is the internal clock mechanism of Oracle. Scn is an important mechanism for oracle recovery. Scn is everywhere in databases. Generally, the scn value is recorded in control

First you need to download HBase latest and stable version: http://www.apache.org/dyn/closer.cgi/hadoop/hbase Decompress the package and move the extracted file to a directory such as/home/user/hbase. $ Cd/home/user/hbaseEnter this directory $ Vi

HEXTORAWSyntax: HEXTORAW (string)Function: converts a binary value represented by a string to a RAW value. string should contain a hexadecimal value. every two characters in String indicate one byte in the result RAW .. HEXTORAW and RAWTOHEX are two

Since MySQL 5.5, the INNODB engine can also be compressed like the MYISAM engine. Of course, the compressed table is okay. You should not INSERT or UPDATE it. DELETE doesn't matter. It's just MARK, and then batch DELETE it. This is the same as the

I encountered this usage while reading the code, but I don't quite understand it. I Googled it. The meaning of this statement is that if the "on duplicate key update" statement is formulated at the end of the insert statement, when the insert row

The Oracle database uses the SNP process to manage and run jobs. The biggest difference between the SNP process and other processes in the instance is that after the process is killed, the system automatically restarts a SNP, therefore, the running

A set of Oracle RAC 10 Gb database, check that the undotbs tablespace is in the recover status, the remote processing process is as follows: 1. Check the database status: Select file #, status from v $ datafile where status = 'recover '; FILE #

I checked the Android source code in Ubuntu Linux today. There is not much space in the root directory. So I want to unload MySQL and install it where I want to install it, so I started to get MySQL again (it seems that it violates my original

Today, I developed a java interface program to insert values from the mysql database to an Oracle database. I think it is quite simple. mysql's query SQL is written, so there is no difficulty. The code for JDBC operations on the database in java has

Oracle Database Synchronization The test is successful between two oracle databases. The following is a summary: Requirements: There are two oracle database servers A and B (A and B can be on the same Intranet or two independent machines on the

Master server: 172.16.15.20Slave server: 172.16.15.30 1. Install mysql # pvcreate /dev/sda5    # vgcreate myvg /dev/sda5   # lvcreate -L 10G -n mydata myvg   # mkdir -p /data/mydata   # mke2fs -j /dev/myvg/mydata   

Oracle spatial creates a spatial field index, creates a field index, and completes an SQL statement instance. // Create a spatial field index for oracle spatial table// ================================================Drop index index_sp_v_gbjj;Drop

The preceding figure shows the unified database cluster. OLTP on the top left adopts shared storage and memory convergence technology. similar to Oracle RAC. the only difference is that there are independent node Management Servers and node

Oracle users only have permission to access other user views: -- Create a userCreate user lf identified by lfPROFILE DEFAULTDefault tablespace userTemporary tablespace tempAccount unlock; -- Grant PermissionsGrant create session to query_dqb;Grant