Database Administrator

-- Read scn information from controlfileSet linesize 140col dummy for a140set linesize 140 numformat 999999999999999999 prompt -- System scnselect checkpoint_change # from v $ database; prompt -- data file scnselect file #, checkpoint_change # from

I encountered an interview question recently, and I was confused. I only spoke about my thoughts. Later, Baidu sorted out my thoughts and recorded them to facilitate future study. (For the interview questions, see the attachment) Related Data Tables:

A trigger is a special type of subroutine stored in a database. It cannot be called directly by users, but is automatically triggered by the system when a specific event or operation occurs. Call execution. The trigger cannot accept parameters.

For mysql using rpm in Linux, we can remove these rpm packages and delete the project directories to uninstall them. This article demonstrates how to download MySQL 5.5.37 in SUSE Linux 10. See the following for details.   1. Environment# OS

The Hadoop and HBase clusters have one NameNode and seven DataNode. 1./etc/hostname File NameNode: Node1 DataNode 1: Node2 DataNode 2:Node3 ....... DataNode 7: Node8 2./etc/hosts file NameNode: 127.0.0.1localhost#127.0.1.1node1#-------edit by HY(20

Paging statement: Oracle: -- This paging query method is not only a simple query for a single table, but also complex for the innermost layer query. -- The multi-table joint query or the innermost layer query contains the same sorting

I. Log Files1. Error Log: Error LogContent: All severe warnings and error messages during MyQL Server running, as well as detailed information about each MySQL Server startup and shutdown.Path: the default storage location is in the data

In many cases, the following situation occurs: if a piece of data already exists in the table, update it. If it does not exist, insert new data. if you do not use the merge syntax provided by Oracle, you may first need to query the database select

Prepare a notebook, single-core CPU, 3 GB memory, and GB hard drive. Prepare a 2 gb usb flash drive. Download the 64-bit version 14.04 (Qilin) ISO on the official website, and download the UNetbootin (Ubuntu dedicated USB flash drive Installation

Intranet connections are generally used in simple projects, but Chinese and foreign connections are common in actual system-level projects. In the use of external connections, I found that many people are confused about the role of the on clause

The official Hadoop website only provides 32-bit Hadoop packages. I installed a 64-bit system, which is naturally unavailable and reports an error. As a result, hadoop cannot be started. libhadoop.so.1.0.0 which might have disabled stack guard.

I. Additional topic Today, we were so sad that when we made datapatch for user data, we imported one more copy of the data each month, and we were shocked by the cold sweat... this is a product environment. If the boss knows it, it will be dead.

MySQL can be viewed as a layer-2 architecture.The first Layer of SQL Layer includes permission judgment, SQL parsing, execution plan optimization, and query cache processing;The Storage Engine Layer (L2) is the implementation of underlying data

Password 420b http://yunpan.cn/QNXXpjP9aBy6v accessIf you want to use sqlplus in Unix or Linux environments, you can turn pages up and down like windows.What should we do?First, check that the OS is installed with the readline tool. Otherwise,

Step 1: Interface Definition: Public interface ICommonDao {List findCollectionByConditionNoPage (String codition, Object [] params, Map orderby ); } Step 2:Classes that implement interfaces: Class entityClass = TUtils. getTClass (this.

1. Assign "system permissions" to someone"SQL> grant connect to aobama with admin optionThis means that the admin database connection permission is granted to "aobama", and "aobama" can grant this permission to others.2. Questions about permission

Previously. Knowledge Point 1: You need to log on to the database and operate create (or replace) directory test_dump as '/opt/test'. test_dump ='/opt/test' cannot be used here ', and/opt/test is enough. You do not need to use/opt/test. Knowledge

Paip. How to resolve the problem of importing data into mysql# --- Cause: mysql import tool bug# --- Solution: Double quotation marks are not included in the phonetic alphabet.Author old wow's paw Attilax iron, EMAIL: 1466519819@qq.comReprinted

1. Introduction to TRIGGERTrigger is a mysql trigger. When a trigger is created, it monitors specific events. When a trigger is triggered, an object is activated to process trigger_stmt, that is, the statement to be executed. For example, when you

I. Problem Introduction ① Assume that Dangdang users bought a book after placing an order. In this case, there is an order with the order number 001 in the database. One of the status fields is "valid", indicating that the order is valid; ② The