Shulou(Shulou.com)06/01 Report--

The function of monitoring is to establish a data connection between the client computer and the central database computer. Once the connection is established, there is no impact on both, and the user on the client on the connection can do any operation and query, even if the monitor has been turned off or broken, but the new remote connection can no longer connect to the database after stopping.

The purpose of UNDO tablespaces:

1. Rolling back a transaction explicitly with a ROLLBACK statement

2. Rolling back a transaction implicitly (for example, through recovery of a failed transaction)

3. Reconstructing a read-consistent p_w_picpath of data

4. Recovering from logical corruptions.

1) rollback the transaction: rollback

2) read consistency: data blocks that are performing DML operations, before other users read the data in the undo before the end of the transaction

Mirror image

3) instance recovery: instance recover (undo-> rollback)

4) flashback technology: flashback query, flashback table, etc.

Because the database stops abnormally, the changes during the period from the last checkpoint of the database to the abnormal stop of the database are only recorded in the redo log file and have not yet been written to several files, so, in the process of database instance recovery, all the redo log files after the last checkpoint are needed, and the corresponding changes are written to the data file.

Adding non-null constraints is to use modify instead of ADD CONSTRAINT

Determine which of the following two situations you can use Data Recovery Advisor to recover?

The one when you cannot start up the database (because required database files are missing, inconsistent, or corrupted) and the one when file corruptions are discovered during run time.

A. The database files are corrupted when the database is open

D. The database is not opening because the required database files are missing

Deferred integrity constraints.

Http://bbs.cqsztech.com/forum.php?mod=viewthread&tid=516

Roles:

Http://bbs.cqsztech.com/forum.php?mod=viewthread&tid=509

SQL tuning.

Http://bbs.cqsztech.com/forum.php?mod=viewthread&tid=518

Which two files in the database can be configured for automatic backup in RMAN?

The automatic backup of the control file occurs independently of any backup of the current control file explicitly requested as part of your backup command. If you enable control file autobackups, then RMAN automatically backs up the control file and the current server parameter file .

SQL*LOADER

Http://bbs.cqsztech.com/forum.php?mod=viewthread&tid=521

In which of the following cases can it be ignored even if the parameter UNDO_RETENTION specifies a value?

For fixed-size undo tablespaces, the system automatically tunes for the best possible undo retention period on the basis of undo tablespace size and usage history; it ignores UNDO_RETENTION unless retention guarantee is enabled.

You want the employee information contained in the flat file to be accessed as part of EMPLOYEES, so you plan to add a column to the EMPLOYEES table to implement

What data type will you use for this new column?

CLOB uses CHAR to save data.

BLOB uses binary to store data.

BFILE's data is stored in the operating system file, not in the database.

LING RAW this data type is used to store binary data that is not interpreted by Oracle.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.