Oracle

Mysql differs from Oraclearticle category : databaseReproduced in http://blog.sina.com.cn/s/blog_5d9ca4ea0100kmhy.htmlFriday went to a company to interview, the company manager asked about The difference between Mysql and Oracle has not been summed

Oracle A Chinese character occupies several bytes, depending on the character set encoding in Oracle View the Oracle server-side character Set select Userenv (' language ') from dual; if shown below, a Chinese character occupies two bytes simplified

Concept:A sequence, in Oracle, is an object that is used to provide an ordered column of data that does not duplicate the value of the ordered data column. 1. sequence can automatically generate unique values2. is an object that can be shared3. a

There are two methods: SCN and time stamp two methods of recovery.I. Recovering deleted and committed data through the SCN1. Obtain the SCN number of the current databaseSelect Current_scn from V$database; (Switch to SYS user or System user

in the work, the statements in the stored procedure are simply noted: /** determine the day of the week */ Select Decode (To_char (To_date (iv_date,' Yyyy-mm-dd ') ), ' Monday ', ' 1 ', ' Tuesday ', ' 2 ', ' Wednesday ', '

--new base station synchronization to battery pack informationCreate or Replace TriggerA_b_test AfterInsert or Update or Delete onBJLT. Basestation--referencing new as New_val old as Old_val--Set the name here, and then you can reference the value

Using NVL (A, B) General function, statistical employee annual income, NVL () acting on any type, ie (number/varchar2/date)General function: The parameter type can be number or varchar2 or date typeSelect ENAME,SAL*12+NVL (comm,0) from EMP;650) this.

---正在执行的select a.username, a.sid,b.SQL_TEXT, b.SQL_FULLTEXT  from v$session a, v$sqlarea b where a.sql_address = b.address ---执行过的select b.SQL_TEXT,b.FIRST_LOAD_TIME,b.SQL_FULLTEXT  from v$sqlarea bwhere b.FIRST_LOAD_TIME between ‘2009-10-15/09:24:47

--View All tables under this user in the ORACLE databaseSELECT table_name from User_tables;--View All tables under All users in the ORACLE databaseSelect User,table_name from All_tables;--View all columns under this user in the ORACLE databaseSelect

There are a number of reasons why Oracle Index failures can be easily caused:1. Use the function on the index column. such as SUBSTR,DECODE,INSTR, and so on, to the index column operation. You need to create a function index to resolve it.2, the new

In college when the major is the database management major, in the school learned a variety of data MSSQL, ORACLE, MySQL.At that time, most of the data learned only a few fur, only in accordance with the book SQL statements, input computer results,

1. View All Users:SELECT * from Dba_users;SELECT * from All_users;SELECT * from User_users;2. View user or role system permissions (System permissions that are directly assigned to a user or role):SELECT * from Dba_sys_privs;SELECT * from

The cache in ASP. NET provides support for SQL dependencies, which means that when the data in a table or row in a SQL Server database is changed, the pages in the cache are invalidated, otherwise the page output remains in the cache. This does

The job's interval is set to sysdate+1 results A lot of customers this time will eventually become a mess of eight bad,or import, or manual execution, and so on, there will be automatic change, and many,Felt somehow, andToday, the Internet search,

1. If you use powerdesigner such a tool, be careful to remove the double quotation marks from the table in the exported SQL statement for the tool.2. When building tables and building fields, use underscores between different words, such as rec_id3.

This article is reproduced from http://blog.itpub.net/28602568/viewspace-1364844/Preface:  Do you want to query, summarize or optimize the rows of SQL every day, the following SQL wants to help    ---query perform slow sql:select s.sql_text every

VARCHAR2 The maximum is 4000 bytes, then look at your Oracle Character set: (select Userenv (' language ') from dual;)If the character set is 16-bit encoded, ZHS16GBK, then each character 16 bits, 2 bytes, so can accommodate 2000 characters.In the

http://blog.csdn.net/zhoufoxcn/article/details/1762351In Oracle, sequence is the serial number, which automatically increases each time it is taken. Sequence is not related to tables.1. Create SequenceFirst, create sequence or create any sequence

Create a new control file based on an existing database#数据库必须是mounted或open状态sql> ALTER DATABASE backup Controlfile to trace;You can use the following shortcut to find the corresponding trace filesql> ALTER DATABASE backup Controlfile to trace;sql>

Oracle's production libraries are all launched in archive mode, and the same is true for non-archived switches and single instances under RAC, both in the Mount mode and in the ALTER DATABASE Archivelog/noarchivelog command. The difference is that