Oracle

Analysis of the merge statement:/**The merge statement is a new syntax for merging the UPDATE and INSERT statements oracle9i.With the merge statement, another table is queried based on the join criteria of one table or subquery,The connection

The connection database suddenly appears with the following exceptionThe following are the solutions that record the following1, check the user's proifle is which, is generally default:Sql>select username,profile from Dba_users;2. View the password

In the first two chapters, we learned some basic SQL language query statements, that is, the database query Language DQL, today we want to introduce the database operation language DMLDatabase, in addition to our query, the main thing is the daily

The following exercises have the default table in the Oracle database as the Principal1. List all departments that have at least one employee.SELECT DISTINCT d.dname from EMP e,dept D WHERE e.deptno=d.deptno;SELECT * from DEPT WHERE DEPTNO in

There are six steps to modifying the Oracle instance name:1. Sqlplus Username/password as SYSDBA, then create Pfile file from SPFile file: Creation Pfile from SPFile2, modify the pfile db_name parameter name is demo, and then save it.3. Create

In the Oracle database, sometimes the ALTER SYSTEM kill session ' sid,serial# ' is used to kill a session process, but after the session is killed with this SQL statement, the database does not immediately release the associated resources. Sometimes

Note: This article does not enumerate all the differences between the two, but in the actual application found in the different function points or processing mode, the reason is recorded, is to remind themselves, do not forgetGROUP BY:(1) Oracle,

During Oracle use, we can generate data files via PL/SQL or spool on spool off, but in some environments we need to process the data through stored procedures, the data is processed, the data files need to be automatically generated, and the manual

Turn characters in Oracle: To_char ()Date of change in Oracle: To_date ()The turn character in MySQL: date_format (date, '%y-%m-%d ') is equivalent to To_char () in OracleDate of transfer in MySQL: str_to_date (date, '%y-%m-%d ') equivalent to

ReproducedIn OracleYou can use the InStr function to judge a string to determine whether it contains the specified character.Finds the specified character in a string, returning the position of the specified character that was found.Grammar:InStr

I. Reasons for not exporting empty tables1, oracle11g default to Empty table is not assigned segment, so use EXP export oracle11g database, empty table is not exported.2. After setting the Deferred_segment_creation parameter to False, both the empty

First, view the constraint information1. Use data dictionary user_constraints to view constraint information for a table in user modeSql> Select Owner,constraint_name,constraint_type,table_name2 from User_constraints;The above SQL statement can

Turn : From http://blog.csdn.net/cyxlxp8411/article/details/7775113> Today , I reported ORA-00054 errors in the drop of a table. sql> drop table T2;drop TABLE T2*ERROR at line 1:Ora-00054:resource busy and acquire with NOWAIT specified or timeout

--stored procedures, querying a table, inserting data into table BCreate or Replace procedurePrc_sg_sjtj_config (P_flag outvarchar2) isBEGIN forC_rowinch(SELECTT.unit_name, T.data_name, T.table_name, T.update_od R, DECODE (T.data_methods,'file',

Let's talk about the difference between in and not in, exists and not exists in SQL. sqlexists 1. in and exists In is a hash connection between the external table and the internal table, while exists is a loop on the External table. Each loop then

Oracle-08-Modify Table Structure (add, delete, modify, and query existing tables) I. Example of adding a primary key when creating a table: Create table stu ( Id number (5) primary key, Name varchar2 (20) ); The above is a primary key constraint.

Oracle-07-Data Type example & query Current System Time & create table syntax I,   Explanation: number (6, 2) specifies four digits for the integer part and two digits for the fractional part. Therefore, the three digits for the integer part 123.456

Oracle Database elementary learning, oracle Database elementary SQL query statement on the first day CMD--SQLPLUS ---- account soctt password tiger, enter the SQL database after the input is complete, it shows that the connection is successful.  

Oracle cascade query and Oracle cascade QueryThere is a method in ORACLE Database for cascading QuerySelect *// The field to be queriedFrom table// Table with child and parent contact IDSStart with selfid = id// Specify a startid (the Field name is

Detailed description of Oracle custom exception examples, detailed description of oracle custom 1. The error box is displayed: Sample Code: Declare v_count number; begin select count (*) into v_count from dept; if v_count Execution result: 2.