Oracle

A problem that bothers me for a long time is basically solved at 8:41 today.The data volume of the database is very large, the query speed is very slow, after indexing "=" search speed problem resolution, but in the search of the SQL statements are

Turn from: http://tenn.iteye.com/blog/99339 In Oracle, to query the top N records on a specific condition, use a rownum.SELECT * from emp where rownum And the book also warns that you can't use ">" for rownum, which means that if you want to

The connection of a table refers to the relationship between tables in an SQL statement, retrieving relevant data from one or more tables, in general, the connection between table and table can be divided into four kinds, namely equal connection,

The materialized view concept is similar to the summary table in discoverer. At the discoverer management end, you can create a different summary table. In the discoverer query, discoverer first parse the query to determine whether the query can use

--Start I personally think that there should not be a null value in the database because he subverted the two-valued logical structure (i.e. true and false), and a three-valued logical structure (i.e. true, false, and unknown) occurred. Because of

Chapter One: journal Management1.forcing Log Switchessql> alter system switch logfile;2.forcing checkpointsSql> alter system checkpoint;3.adding Online Redo Log groupssql> ALTER DATABASE Add logfile [Group 4]Sql> ('/disk3/log4a.rdo ',

Oracle View table space usage (including temporary tables) SELECT * FROM (select A.tablespace_name, To_char (a.bytes/1024/1024, ' 99,999.999 ') total_bytes, To_char (b.bytes/1024/ 1024, ' 99,999.999 ') free_bytes, To_char (a.bytes/1024/1024-b.bytes/

Cursors are buffers of data, plsql do not allow output of set values, only single properties, cursors you can interpret as Ajax RowData 1 View the stored procedures under the current User: SELECT * from User_procedures;2 View all users (note that

See a lot of people forKeepDon't understand, here's an explanation.Returns the row ranked theUsing Dense_rank2 Kinds of values:Dense_rank theDense_rank LastInKeep(Dense_rank theORDER BY SL) The result set is to take the example of Max and Min.Sql>

Alternative use of Oracle profiling functions: Over (partition by ...) in the analysis function using case when; Cases: Sql> with Pctest as ( 2 Select 1 IDs, ' A1 ' name from dual 3 Union 4 SELECT 1 IDs, ' A2 ' name from Dual 5 Union 6

http://cherryqq.iteye.com/blog/855022 Http://www.cnblogs.com/lumnm/archive/2012/08/31/2666155.html The Oracle job is also executed after Oracle restarts. One: The simple test job creation process case: 1, first create a job_test table, the field

Pre-preparation work:Back up all the old Oracle files, delete the old directories, and then reinstall Oracle, the directory is the same as the old directory (if not, there are more places to modify).Install Oracle only, do not create DATABASE, if

Case when it is convenient to use when different conditions require different return values, you can use them when assigning values to variables, or you can use them in a SELECT query statement.Case Search Statement format: CaseWhen condition 1 then

The individual understands Oracle permissions as three classes, System permissions, object permissions, and session permissions.Correspond separately:Dba_sys_privs;Dba_tab_privs:Session_privs; Of course there's

Oracle 10g new features-code obfuscation Author: Fuyuncat Source: www.HelloDBA.com Oracle 9i Previously, a command ' warp ' was provided to encrypt the code. But it's command-line, it's script-oriented. In 10g, Oracle Package DBMS_DDL

a table function can accept a query statement or a cursor as an input parameter and can output multiple rows of data. The function can be executed in parallel, and the data stream can be continuously output, known as pipeline output. The table

Oracle Predefined 21 System exception types Access_into_nullNo object definedCase_not_foundIf the case does not contain the corresponding when, and if no ELSE is setCollection_is_nullCollection element not initializedCurser_already_openCursor

Since last week, the server Oracle database problem, less than half a day, will report Maxsession (150) of the problem, must be the database session exceeds the maximum number.Because the server is running a file transfer application, the request

Most customers have their own database servers to manage some of their key data. So what if we need to use this data in our project and the customer is not allowed to insert that data into our project database server? One solution is to create a

In recent days has been to oracle-sql problems, involving some of the usual not used things, but also here depressed for a long time. Now the problem has been solved, though not perfect. But let's share it with you. One of the row and column