Oracle

The parent-child relational record set or tree-like data record set is a common data organization form in software development. For example, the organizational structure in the office system, such as the province, city, and region in the user system,

1. What is registration? Registration is to register the database as a service to the listener. The client does not need to know the Database Name and Instance name. It only needs to know the service name provided by the database to external users

According to the definition of NULL, NULL indicates unknown. Therefore, the results of two NULL comparisons are neither equal nor unequal, and the results are still unknown. According to this definition, the existence of multiple NULL values should

Example of creating and using oracle Stored Procedure 1. Create a stored procedureCreate or replace package pk_1 as // statement for creating a packageTYPE cur is ref cursor; // declare a pointerProcedure p1 (cr out cur );End; / Create or replace

Apart from significant technical differences between SQL Server and Oracle databases, there are also significant differences in implementation costs. I will share some of my views on this topic and hope to communicate with you. I. Oracle is

Today, I used hibernate to access the oracle database and found a problem;Java code icacert IcaCaCert = icaCaCert. findByCertSerialNumber (certSerial);  An exception is reported: the stream is disabled. Looking at the database, we found that there

Any database may have certain security risks during its long-term use. For database administrators, a complete set of database backup and recovery mechanisms should not only be intended for the secure operation of computer operating systems. When

Today, I received an email from the customer saying that the database had a lot of locks every day at last week. I collected AWR information from the customer and found that the top 5 ranked second was enq: TX-row lock contention.SQL> select SESSION_

Flash back is the biggest new feature of oracle10g. Most of the flash back content has been sorted out before, including flash back database, flash back Delete table, delete table, and Flash back version query, this topic describes how to ensure the

  In Oracle, a statement block is used as a default transaction. That is to say, if you only execute a block of ORACLE statements, it is executed in the form of transactions by default. Create or replace procedure sp_EditInlayOut ( Fid number, --

Case 1 of Oracle online Log Recovery: it is a good solution to the loss of a single member in a multi-path log. You only need to copy the intact online log to the bad log. Case 2: All members of non-current online logs lose the simulated environment:

"The cost of configuring the query optimizer is expensive, but it is worth the effort ." (Note 1) In fact, I have seen many sites that underestimate the importance of good configuration. Sometimes, I even had a heated discussion with some people who

Full Oracle exercise PS: All Tables come from the tables of SCOTT users in Oracle, and should be known to beginners. I deleted the SMITH of the emp table without rollback, so the results may be slightly different. 1. SELECT * FROM emp WHERE deptno =

Oracle cannot modify the data type of an existing column if there is data in the table. However, you can create a temporary column, copy the data of the column to the temporary column, delete the original column, and modify the name of the temporary

To implement conditional statistics in the count () function, use the SUM function to replace the count () function and use the SUM function to implement conditional statistics, you can use the case when statement or Decode function to convert the

Modify oracle memory usage # Su oracle $ cd $ ORACLE_HOME $. /sqlplus/nolog> connect/as sysdba;> show parameter sga; (view memory usage) name type value values ----------- ------------- lock_sga boolean FALSE pre_page_sga boolean FALSE sga_max_size

How to cache tables in oracle to memory because some static data tables are frequently accessed in the database, you can consider caching these tables with a small amount of data to the memory. There are two methods: for example, cache the fisher

ORACLE 11g rac Listener Configuration (instance sharing) after a user RAC installed on QQ last two days, how to configure the listener? Below I will share an instance Environment Information cat /etc/hosts192.168.1.11 racdb1 192.168.2.2

Oracle-user-managed backup (1) I. first, you must know the table space and file information in the database. There are several performance views: v $ datafile, v $ tablespace, v $ tempfile, v $ logfile, v $ controlfile, dba_tablespaces,

Oracle-user-managed backup (ii) I. What will happen if the host is shut down abnormally when the tablespace is in backup mode? Open the first session window, Log On As A sys user, and place the tablespace users in backup mode. SQL> alter tablespace