Oracle

1. System tablesThe system parameters of the Oracle database are stored in the database and can be queried by the user Sysytem through Sqlplus. A few important tables or views are as follows:V$controlfile: Control the information of the

Common Sql*plus commands and environment variables----------------------------------query table Structure Command: describe (abbreviated DESC)Set Display output width: Set line [size] {80|n}List the statements for the SQL buffers: list (abbreviation

SetLinesize -SetPageSize $columnblocker format A10columnblockee format A10columnblocker_sql format A30columnblockee_sql format A30columnblocker_machine format A30columnblocker_program format A30columnblocker_event format A30columnblockee_machine

After the Oracle database is started, you can view all the parameters used by the Oracle database by using the select * from V$parameter statement . For Oracle 's parameter files, it is divided into spfile binaries and pfile text files, and now the

Objectivethese last few days have been working with Oracle database, due to previous Oracle The study is not deep, just put Oracle As a data source to use, a lot of things do not know very deep, such as databases, database instances, table space,

Today in the local configuration of the Oracle client, once again need to link the service side of the LAN machine, the estimated need to configure the tnsnames.ora file, make a record, prevent the next use, once again search configuration method:

We all know that PL/SQL can copy data to Excel, and we can also insert data into the database via Excel.Let's take a simple example with a demoFirst, we create a table testCREATE TABLE Test (ID number);Then we execute the following statementSELECT *

Oracle 's data structures are divided into physical and logical structuresPhysical Structure: Data block of the operating system-> data file datafilesLogical Structure: Minimum database block-->extent-->segement--> Tablespace-->databasesWhere for a

When creating an index, we often want to be able to estimate the size of the index to assess the impact on an existing engineering environment, and we want to create an index that minimizes the impact of the engineering environment we're running and

Oracle IndexManaging indexes-Introduction to Principles? IntroducedAn index is a data object used to speed up data access. Proper use of indexes can significantly reduce I/O times and thus improve data access performance. There are many kinds of

Install Client services only to use PL/SQL to connect Oracle========================================First download the Oracle corresponding client software, such as Instantclient_11_1 followed by the following steps.1. Place the instantclient_11_1

Today in the Oracle database is encountered Oracle cannot delete the current connection user, after the search can be resolved as follows.   Prompt when deleting a user in Oracle: Oracle cannot delete the current connection user can use the

Background:Early in the project is the establishment of a server two instances, the client configuration two connections, now need to consolidate two instances of one instance, requires that the client's configuration is not changed.For

Managing a Oralce Software:How to manage a database, what knowledge you need to know.1. Installation: location, character set2. Build Library: What database name3. Database Startup:Nomout: Read parameter file, some initialization settings

#1, select the most efficient table name order The Oracle parser always processes the table from the back of the from right to left, so the from rightmost table will be treated as the driver table precedence, and when there are multiple table

SQL>descdbms_random: Querying stored procedures and functions under the Dbms_random packageA, value () is used to return a random number between two values, value (Low, high) SQL>SelectDbms_random.value () fromDual: The default is 0 to 10.05368242484

Oraclesqlnotin multi-field comparison exampleSelect * from (select t2.cadastralno parcelid, t1.pkid taxpayerid, t2.taxtype taxtype, t1.booktype taxpayertype,T2.cadastralno parcelCadastralno, t2.landuser parcelLanduser, t1.payername taxpayernameFrom

Orcal database review notes① In SQL, which is not equal to <> eg: select * from emp where deptno <> 10; ① fuzzy match keyword is like _, which represents a character, % indicates 0 or more. eg: select ename from emp where ename like '_ A % ';②

Introduction and instance demonstration of blocked in Oracle RAC environment, racblocked The blocking in the RAC environment is different from that in a single instance, because we need to consider the session in different instances. That is to say,

PL/SQL-variables and plsql Variables 1. PL/SQL Introduction PL/SQL is also a program Language called Procedural Language/SQL ). PL/SQL is an extension of oracle's SQL statements. It adds the features of programming languages to the use of common SQL