oracle sql by example

how to create a session-level temporary table.Create global temporary table admin_work_area(Startdate DATE,Enddate DATE,Class CHAR (20 ))On commit preserve rows;EXAMPLE: Session 1:SQL> drop table admin_work_area;SQL> CREATE GLOBAL TEMPORARY TABLE admin_work_area2 (startdate DATE,3 enddate DATE,4 class CHAR (20 ))5 on commit preserve rows;

Tags: Oracle administrator shared database userOracle SQL performance Optimization in layman'sOracle holds executed SQL statements in a shared pool of memory, which can be shared by all database users. When you execute an SQL statement (sometimes called a cursor), if it is exactly the same as the previous executed stat

want to find a solution from the perspective of database technology. For example, Oracle's long-time query if undo data (historical data) to overwrite, Oracle will throw an exception "ORA-01555: Snapshot too old", if this problem occurs, from the perspective of system design, why are there so many queries? Why are other transactions updating data in this query? Is it enough to query these queries only once

Use Oracle SQL * Plus to analyze SQL I. Analyze and execute SQL statements SQL> set autotrace on; Description: Enables automatic analysis statistics and displays the running results of SQL statements.

Oracle BASICS (5) Advanced pl/SQL (paging process)Compile the paging process to implement the paging process through pl/SQL, and then step by step from simple to difficult. The purpose is to familiarize yourself with the various stored procedures, packages, and cursors of pl/SQL through this case, learning how to call

Upgrade a single Oracle 11.2.0.1 instance to 11.2.0.3. Oracle upgrades are similar. Upgrade Oracle software and then Oracle instance. The patchset No of Oracle 11.2.0.2 is 10098816. For details about this Patchset, refer to the following link:

= 0license_sessions_warning = 0SCN Scheme 2Using log_archive_dest Parameter Default valueLicense_max_users = 0SYS Auditing is disabledStarting up ORACLE RDBMS version:9.2.0.1.0.System parameters with Non-default values: We can see that after the problem, some engineers tried to recover several times, including the offline datafile action. The ORA-00600 [4000] error occurred when the database was last opened more than once, and it was stuck on this e

changed only when all values of a column are empty. The column not null can be defined only when all values of a column are not null. Example: Alter table dept modify (loc char (12 )); Alter table dept modify loc char (12 ); Alter table dept modify (dname char (13), loc char (12 )); Search for undisconnected connections Select process, osuser, username, machine, logon_time, SQL _text From v $ session a, v

because the RDBMS core module will return the results immediately after the conditions of the subquery have been met. Example:(inefficient):SELECT DISTINCT dept_no,dept_name from DEPT D, EMP EWHERE d.dept_no = E.dept_no(efficient):Select Dept_no,dept_name from DEPT D WHERE EXISTS (select ' X 'From EMP E WHERE e.dept_no = d.dept_no); server/' target= ' _blank ' >sql statement in uppercase; Because

How to check whether the SQL statements are correct when executing large SQL statements in Oracle stored procedures? A large SQL statement is sometimes used in the preparation of a stored procedure in Oracle. However, you cannot see the

triggersA. Enabling and disabling triggers: When to prohibit: Prohibit data import and exportsql> ALTER TRIGGER aiu_itemfile DISABLE;sql> ALTER TRIGGER aiu_itemfile ENABLE;B. recompiling a trigger: After a database object has changedC. Deleting a triggersql> DROP TRIGGER Aiu_itemfile;19. Triggers and stored proceduresTrigger Stored proceduresWrite no parameter, return value has parameter, return value (parameter)Write cannot commit or rollback canCal

oracle| Performance | optimization | statement 1. Choose the appropriate Oracle OptimizerOracle's optimizer total of 3 kinds A, rule (rule-based) B, cost (based on costs) C, CHOOSE (optional) set the default optimizer to pass various declarations of optimizer_mode parameters in the Init.ora file, such as Rule,cost,choose,all_rows,first_rows. You will of course overwrite it at the

the DBA The growth of Blue-Chase DBA (3): antique operation, data import and export become a problem The growth of Blue-Chase DBA (4): Recalling the youth, and then explore Oracle installation (Linux 10g, 11g) The growth of Blue-Chase DBA (5): No talking about business, annoying application system The growth of Blue-Chase DBA (6): Work and life: small skills, great people The growth of Blue-Chase DBA (7): Basic Command, foundation stone The growth of

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Some customers storage exception power failure, resulting in database startup reported ORA-01172 error, resulting in the database cannot openDatabase startup reports ORA-01172 errorWed Mar 23 14:16:23 2016ALTER DATABASE OPENWed Mar 23 14:16:24 2016Beginning crash recovery of 1 threadsParallel recovery started with 15 processesWed Mar 23 14:16:24 2016Started redo scanWed Mar 23 14:16:25 2016Completed redo scan62588 redo blocks read, 15 data blocks need recoveryWed Mar 23 14:16:25 2016Started redo

method) Select count (*) from tab1, tab2 execution time 0.96 seconds Select TAB2 as the base table (poor method) Select count (*) from tab2, tab1 execution time 26.09 seconds If more than three tables are connected for query, You need to select an intersection table as the base table, which is the table referenced by other tables. For example: The EMP table describes the intersection between the LOCATION table and the CATEGORY table. SELECT *From loc

Troubleshooting of SQL plus logon failures caused by su switching in Oracle Problem description:The Oracle database in the production environment suddenly fails to log on, and the oracle database in the rlwrap production environment suddenly fails to log on. rlwrap sqlplus "/as sysdba" reports the following error: rlwr

This article introducesSQL migrationThe second part: create a data file library Migration Repository ). 1. Connect to Oracle In the connection window on the left of the program, click the plus sign to add oneOracle DatabaseFor example: After the configuration is complete, click Connect to connect to the database. 2. Create a user Open the connection to Oracle Da

for database operations change, the need for a more complex ETL solution in SQL Server has changed. SSIS is the end result of many years of customer feedback and Microsoft modifications. The basic premise of Data transformation in SQL Server has not changed, but the tools and processes to complete the ETL task have fundamentally changed. SSIS has more extensive functionality than it did before. This docum

for SQL optimization are emerging, writing your own SQL tools is always the best way to solve the problem:Select executions, disk_reads, buffer_gets,Round (BUFFER_GETS-DISK_READS)/buffer_gets, 2) hit_radio,Round (disk_reads/executions, 2) reads_per_run,SQL _textFrom v $ sqlareaWhere executions> 0And buffer_gets> 0And (BUFFER_GETS-DISK_READS)/buffer_gets Order by