Oracle

Basic concept of oracle: Database vs Instance is the most confusing term for oracle users, especially those with ms SQL server experience. The two concepts www.2cto.com are actually quite simple to understand. Let's take the notepad notebook as an

Oracle query conditions are case-insensitive. For example, if the storage name job is queried, JOB_REPORT_COUNT_INFO and job_clearinvalid can be displayed. The conditions for www.2cto.com are =. You can write upper (pro_name) in this way) = upper

Oracle service description 1. OracleCSService process: ocssd.exe cluster Synchronization Service (css)-manages cluster configurations. By controlling nodes, the member clusters and notification members are added to or removed from the cluster when a

Oracle uses log recovery and archive mode to modify archive Mode Modify logs // view the archive mode www.2cto.com archive log list; // view the archive parameter show parameter db_recovery // log archive path: F: \ oracle \ product \ 10.2.0 \

Today, I want to go into something meaningless: many people know that it is meaningless to use null values for comparison. But have you ever actually tried it?Try to see if there are some strange phenomena. Let's take a look at the following two

Oracle commit detailed usage commit working process before commit is submitted Oracle generates a revocation record in the SGA undo segment buffer, the undo record contains the old value www.2cto.com for updating and deleting table rows. Oracle

The Cast usage of Oracle is often seen in the SQL of the predecessors, for example: www.2cto.com with t as (select level | ''l from dual connect by level select cast ('192. 100' as number (123) as num from dual;

Various database query statements 1. String connection query Oracle Database select userid, USERNAME | ':' | useremail nameandmail from student where username is not null and usermail is not null; when using the CONCAT function, note that this

Oracle Advanced Statement 1. oracle copy table: create table A as select * from B 2. oracle Export Import Database: the database TEST is completely exported, and the user name system password manager is exported to D: \ daochu. exp system/manager @

Method 1 of Oracle cross-database query and replication table data: currently, most databases require distributed query. The following describes how to configure cross-database access in oracle. For example, there are two database servers and two

Oracle date processing -- calculate the year month day select to_char (sysdate, 'yyyymmdd'), sysdate from dual; -- calculate the year month day system yesterday select to_char (sysdate-1, 'yyyymmdd'), sysdate from dual; -- calculate the day before

SQL of Oracle Database --- select 2Previously, I talked about some simple use of the select statement. This time, I will learn more about the select statement.Including: where condition limit query, range query, fuzzy query, and sorting of query

The experiment in Using SQL * Loader to create an external table contains a txt text file. Based on this text file, use SQL * Loader to create an External Table.1, create a control file [oracle @ vmoel5u4 ~] $ Vi car. control load datainfile

Oracle changed the field type from number (2) to number (2, 1). This afternoon, when I did something myself, I found a small problem. When I created a data table, the course_credit field of course is set to the number (2) type, which leads to the

Oracle Trigger 1-Introduction to Reasons to Use Trigger: ■ Automatically generate calculated column values ■ Log events ■ Gather statistics on table access ■ Modify table data when DML statements are issued against views ■ Enforce referential

The specified HINT in the background is automatically removed because the database version is upgraded, and some HINT has no effect (for example,/* + RULE */), and it is decided to clean it from the background, however, there are nearly 2000 objects

Tips for configuring Oracle sqldev shortcutsWell, I have not fully studied sqldev, but it is not very convenient to use in a few places. I found that I can modify the shortcut key to correct it.1. Code intelligent completion promptAll the shoes that

Multitable insert command conn hr/hr1, create test table SQL> create Table small_orders (order_id int, order_total number, sales_rep_id varchar2 (4), customer_id varchar2 (10); table created. SQL> create table medium_orders (order_id int,

Oracle SqlPlus statement bit by bit records start Oracle listening: lsnrctl start view Oracle listening status: lsnrctl status start OracleServiceORCL service: net start OracleServiceORCL view the service name of the Oracle database to be connected,

Oracle built-in table [SQL] -- Beginning with oracle common system table/* dba ..... dba_users Database User Information dba_segments table segment information dba_extents data zone information dba_objects database object information dba_tablespaces