Database Administrator

[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>

Solutions for moving Oracle tablespace data files Solution 1: Move regular tablespace (non-system tablespace) data files /************** When the disk space of a database server is insufficient, move the regular tablespace data file ************* ***

Statement used to query dead transactions in Oracle Statement used to query dead transactions in Oracle SQL> SELECT KTUXEUSN, KTUXESLT, KTUXESQN,/* Transaction ID */2 KTUXESTA Status, KTUXECFL Flags, KTUXESIZ3 FROM x $ ktuxe4 WHERE ktuxesta! =

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

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;

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

[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

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,

From the perspective of performance, we will talk about the selection of SQL Server clustered index keys,Introduction In SQL Server, data is stored by page. After a clustered index is added to a table, SQL Server performs data search based on the

[Reconstruction of individual data centers]-create a database trilogy and a data center Trilogy After edification of the basic three-layer idea, we will immediately enterReconstruction of personal IDCI feel like I am a cainiao, and I have a long way

Rubbing people and chores-constantly updating, and constantly updating1. After finishing the lv layout and adding datafile, we can find the big tablespace ....2. Add a bare device datafile without r3. Access the cde interface through the xmanager

For different database versions of session_cached_cursorsFor the session_cached_cursors value, different db versions have different default values:9i is 010.1 010.2 is 2011.1 is 5011.2 is 5012.1 is 50It is worth noting that this parameter is a

[Translated from mos] In the rac database, the HC _ . dat file is used by instances under other Oracle_Home instances .,In the rac database, the HC _ . dat file is used by instances under other Oracle_Home instances.Reference Original:RAC database

Oracle memory management (one): oracle Memory Management [In-depth analysis of oracle-eygle] Study Notes 1. Memory Management   The memory used by the ORACLE database mainly involves two aspects: PGA and SGA.  1.1 PGA Management PGA refers to the

[Translated from mos] The v $ undostat view is not updated every 10 minutes. v $ undostat has only one row (one rows) and mosundostat. The v $ undostat view is not updated every 10 minutes. v $ undostat has only one row (one rows) Reference Original:

Overview of database systems-[04] index and database system overview 04 1. Index Overview  Index creation is an effective way to speed up the query. You can create one or more indexes on the basic table based on the needs of the application

MongoDB aggregation operations, Introduction to aggregation An aggregation operation is an operation that records data and returns computation results. MongoDB provides rich aggregation operations to detect and execute computation on datasets. Data