Database Administrator

1. Obtain the current date and time Select sysdate from dual; 2. Get the date and time of the Current System Select to_char (sysdate, 'yyyy-MM-dd hh: mm: ss') from dual; 3. MONTHS_BETWEENdate1, date2): returns the number of months between date1

-- ==================================== -- Oracle cold backup -- ==================================== I. Cold backup When the database is closed, all physical system files are copied, which is also called offline backup. Suitable for non-archive

If we use the Select statement to query data from the database, how does the Oracle database work? What can we learn from this? Next, we will combine a simple select statement to look at the operating mechanism of the Oracle database background.

MySQL server has many parameters, but for most beginners, many parameters often make us feel overwhelmed. But which parameters need to be adjusted and which have the greatest impact on server performance? For Myisam storage engine, there are two

When MySQL uses the innodb engine, the page size defaults to 16 KB, which is too large for many applications, many applications that run well in ORACLE, for example, migrate data to innodb, find that the IO pressure is too high. MySQL does not

MySQL master-slave synchronization is a mature architecture: advantages:① The query can be performed on the slave server (that is, the READ function we often call) to reduce the pressure on the master server.② Back up data from the master server to

To save system resources, we usually stop some services and start them the next time we need them. However, we often forget. For example, the MSSQL database that I connect to my local machine cannot be connected. 650) this. width = 650; "style ="

This blog post aims to read and understand your own books and use this picture to explain. If there are any mistakes, I hope you can correct them and share them with us for the purpose of mutual discussion.First, let's introduce the source of the

What is an error buffer?In MySQL, the Error Buffer only records the last error. If a new error is generated, the old one will be overwritten. If you want to know what errors are generated, you must follow "show warnings" or "show errors" after each

MySQL version 5.5.19master) Mysql5.1.59slave) During replication from a lower version to a higher version, MYSQL restarts repeatedly and a BUG message appears in the error log. 650) this. width = 650; "border =" 0 "alt =" "src ="

  This is the configuration of the master database for master-slave replication in mysql:  server-id       = 1   log-bin=/mysql_log/binlog/bin-log   slave-skip-errors=1062,1205   max_binlog_size = 500M   binlog_cache_size = 128K  

We do not need to migrate data from ORACLE to MYSQL. Below I have written three simple MYSQL functions. For your reference.Is it time? DELIMITER $$    USE `ytt`$$    DROP FUNCTION IF EXISTS `is_date`$$   

Liquor-making tea: a large number of sequents and examples are referenced in the book. The notes made by tea after the experiment are uploaded to the blog. Anyone with copyright rights can directly remove the article. Thank you for your

I just came back from Huilongguan, and now it's am. The miserable itrip man started to work.A two-node oracle 11g rac with the host names rac1 and rac2 respectively. The instance names are db4qg_1 and db4qg_2. The effect required is that the rac1

We know that temporary tables have the following features:1. At the SESSION level, a SESSION is automatically dropped once it is disconnected. 2. It depends on the default engine. If the default engine is INNODB, And you are crazy about using

MySQL architecture is master-slave), master failure is automatically switched to slave. You can also set it to a dual master, but there is a drawback: when the pressure on the master is very high, the latency from the top is very large, such as 2000

Original article address: Stairway to SQL Server Indexes: Level 1, Introduction to Indexes This article is part of the SQL Server Index advanced series Stairway to SQL Server Indexes. Indexing is the basis of database design and shows developers the

On oschina just now, I saw a message about the SQL injection vulnerability on the 12306 website of the Ministry of Railways, which is an absolute high-risk level. I looked at it and it was speechless. This kind of mistake is too low-level and should

I saw some people discussing the difference between pre-read and physical read on the internet today. I personally think that both physical read and pre-read operations require reading data from the disk to the memory, the reading time is different,

The company's oracle11gRAC (2-node) database uses the storage of ASM, the operating system is RHELThere is only one control file. Yesterday I added a control file. In sqlplus, alter system set control_files = '+ DATA/kabiz/controlfile/current.260.797