Database Administrator

I have previously set up a mongodb development environment. The operating systems are all 32-bit. Yesterday I found a 64-bit win7 system and installed it on the virtual machine. The 32-bit system runs a 64-bit Virtual Machine. No problem. The

1. ConceptsHadoop is an Apache open-source distributed computing framework, which includes DFS and MapReduce, a distributed file system. MongoDB is a document-Oriented Distributed Database and NoSql, here we will introduce a MongoDB Hadoop driver.

The following table lists the types of locks added to the table and the compatibility between the locks and other types of operations. Table 13-3 Summary of Table Locks SQL Statement Mode of Table Lock Lock Modes Permitted?

Business Needs: I created a table named t_0_mtbuf in Oracle and created it using a statement for creating a common table. In fact, this table serves as a temporary table, namely: In java, select 1500 entries each time, insert them into the sqlserver

Previously, we have set up the PAA environment for rac and data guard of a single instance database (see). To facilitate the switchover operation, we have configured data guard broker for the operation here! In the rac environment, you need to store

The following are related records of installing PostgreSQL 5.5 On CentOS 9.1. (1) download the postgresql9. 1 RPM installation package from the http://yum.pgrpms.org/repopackages.php[Root @ server1 ~] # Wget http://yum.pgrpms.org/9.1/redhat/rhel-5-i3

As a DBA, we mainly perform the following operations for table maintenance:1. Increase the table space size.All the tables we create are stored in the tablespace. When the tablespace creation attribute is automatically extended, we usually do not

Steps 1-7 below are for the root user 1. hardware environment requirementsCheck content minimum value check command referencePhysical memory 512 M # grep MemTotal/proc/meminfoSwap space 1.0 GB or 2 times memory size # grep SwapTotal/proc/meminfo/Tmp

1. Use stored procedures (1) create a packageSQL code CREATEORREPLACEPACKAGE TESTPACKAGEAS TYPE Test_CURSORISREFCURSOR; EndTESTPACKAGE; (2) create a Stored Procedure SQL code CREATEORREPLACEPROCEDURETESTC (p_CURSOROutTESTPACKAGE.

1. Compare the difference between the current time and the specified time in minutes:Select sysdate,Sysdate-to_date ('2017-04-03 13:45:39 ', 'yyyy-mm-dd hh24: mi: ss ')From dualOutput result: AM 10:45:56 0.875196759259259Select sysdate, to_date ('201

The generated environment is different from the actual environment execution plan, so the real environment does not go through the index. The test environment takes several seconds and the real environment lasts for more than two minutes. Plan

Recently I tested nosql. After HandlerSocket is installed, the primary key of the table to be created is the auto-increment id. The result is the ID specified during the insert operation, and a conflict occurs .... error 121 is reported. After

When you use Crosschecking on multiple nodes, you can configure the cluster so that each node in the cluster can access all Database backups, regardless of who generated the database backup. If your cluster is configured like this, you can allocate

Load dataThe usage is as follows: Load data [LOW_PRIORITY | CONCURRENT] [LOCAL] INFILE 'file_name.txt' [REPLACE | IGNORE] INTO TABLE Tbl_name [FIELDS//Field [Terminated by 'string']//FieldRoomDelimiter [[OPTIONALLY] enclosed by 'Char ']//Including

Integrity constraintsIntegrity constraints are used to enhance data integrity. Oracle provides five integrity constraints: CheckNOT NULLUniquePrimaryForeign key Integrity constraints are a rule that does not occupy any database space. Integrity

Error:1)Caused by changing the master:Last_IO_Error: error connecting to master 'repl1 @ IP: 100'-retry-time: 60 retries 2)Stop the slave process without unlocking:Mysql> stop slave;ERROR 1192 (HY000): Can't execute the given command because you

Structured Query LanguageThere are four types of statements:Data Query Language DQL-Data Query Language SELECTData Manipulation Language DML-Data Manipulation Language INSERT, UPDATE, DELETEData Definition Language DDL-Data Definition Language

Log on to the database using the following methods in Oracle in Linux: sqlplus/nolog conn/as sysdba, but it gets stuck at the conn/as sysdba step and cannot be logged on, and check whether the listening status does not respond. This is a bug in

79Adump 4717Bdump 2572945Cdump 0Dpdump 0Pfile 22310Scripts 32879Udump Search for other people's SolutionsDirectly delete files starting with "a" from bdump.Remove files under cdumpHow can cdump increase rapidly? Appendix:Recently, the company

For the four phases of Oracle Database startup, see: 1. The database is in the SHUTDOWN status. In this status, the database is stopped. External data requests cannot be accepted. You cannot use the operating system command ps-ef | grep ora to see