Database Administrator

I have been very interested in the principles and practices of distributed systems for a long time, and I have been very curious about Mongodb. I have finally had time to experiment with it! I set up a Replica Sets + Sharding test cluster

Crs_stop-all Crs_stop-all When crs_stop-all is executed in RAC, the system prompts that some services cannot be stopped. When crs_stat-t is used to check the status, the state of the services that cannot be stopped is UNKNOWN,The service cannot

The following is what I encountered during the test. I did not have it before, but it seems that I can use lower case letters. But today, when I change the archive location, I can only use upper case sid. In my environment, Oracle sid is case

To solve this problem, you can use the following command to change the attributes of a partition table: SQL> alter table DOM_REAL_CATEGORY_FL enable row movement; Table altered. Changing the partition key value of the Partition Table means that

The default "&" in SQL * Plus indicates the substitution variable. That is to say, as long as the symbol appears in the command, SQL * Plus requires you to enter the substitution value. This means that you cannot input a string containing this

When you access a table, an error similar to the following occurs:ORA-01578: Oracle data block upted (file #6, block #344)ORA-01110: data file 6: 'd: \ ORACLE \ PRODUCT \ 10.2.0 \ ORADATA \ ORCL \ TEST. DBF'The reason is that the data file contains

Follow the steps of configuring dbstart for Oracle 10g on the Internet to enable auto-startup. the startup is successful and the record is as follows: 1. Modify the dbstart script:$ Vi $ ORACLE_HOME/bin/dbstart# ORACLE_HOME_LISTNER

1. The LONG data type stores variable-length strings with a maximum length limit of 2 GB. 2. For text that exceeds a certain length, the LONG type can only be used for storage. Many objects in the data dictionary are defined as LONG. 3. The LONG

Step 1: su ipvs Step 2: bash-4.2 $/usr/pgsql-9.1/bin/initdb-D/var/lib/pgsql/9.1/data/, press enter and the following message appearsThe files belonging to this database system will be owned by user "stored s ". This user must also own the server

Edit script file[Python] Db_user ="Root" Db_passwd ="123456" Db_host ="Localhost" Backup_dir ="/Usr/local/apache2/htdocs/backup" Time ="$ (Date +"% Y % m % d % H % M")" MYSQL ="/Usr/local/mysql/bin/mysql" MYSQLDUMP

The Spool buffer pool technology in Oracle can be used to export Oracle Data to text files. 1. Enter the buffer start command in Oracle PL/SQL and specify the output file name: Spool d:/output.txt   2, Set heading off -- remove the field name Set

First, change the lazy property to false. Type 2: Add OpenSessionInViewFilter org. springframework. orm. hibernate3.support. OpenSessionInViewFilter flushMode AUTO OpenSessionInViewFilter /* The above two methods have some problems. Third,

Find something to do. After this project was completed, I found that on-site testers generally did not grasp the SQL statements at the front-end (that is, they clicked the operations on the front-end interface and then went to the database to find

Conn/as sysdbaCreate undo tablespace undotbs3 datafile 'd: \ lx \ undotbs03.dbf 'size 2 m;Alter system set undo_tablespace = undotbs3; Sess1:~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~Drop table test_undo;Create table test_undo as select *

Table: msg_content Table: msg_contact_person Expected results Key Point Analysis: the difference between the result table and table 1 is that the real name of table 2 is added to the "er" field. Implementation Method: Step 1: Split the fields in

Multi-row function Aggregation FunctionExecution sequence:TName -- where -- group by -- having -- order by (select) The alias in the current clause cannot appear in the where clause, nor can the aggregate (Group) function be used. When clustering

Branch Structure Decode   If expr1ThenAction1Elif expr2ThenAction2...ElseDefault_actionFi Decode (expr1, search1, result1, search2, result2,..., default)Only equivalent comparison can be performed. SQL> select ename, deptno, decode (deptno,10, 'aaa

First, the previous image shows the truth. Note: 1. Read a data table with more than rows, and then write data to the local table. 2. Tables of the big field type are not included. Note: 1. I recently performed data import/export operations.

1. The following Code creates a top100cur () function, which returns an anonymous cursor. -- Drop function top100cur (); Create FunctionTop100cur ()ReturnsRefcursorAs$ Declare Abc refcursor; Begin OpenAbcFor Select*FromPersons limit 100;

The following is an example of 10046, which can be used to analyze specific SQL Execution plans and make a record! Set 10046 events for SQL tracking. You can set different tracking levels. Level 0 disables SQL tracing, which is equivalent to SQL