Oracle Learning (1) - Introduction to Oracle for 15 days

* A few days ago I shared a bit rubbish after graduation learning java and Oracle article, could be determined to enter the IT graduates or people a little help. Many current students email asking how I should be learning Oracle, while the project is now into the last chance of a little free time. Review about Oralce basis points while doing notes, also hope to give colleagues the need to drop in the bucket.
To affirm this: I mentioned here just to get into the basics, but as long learned that a project is enough to meet the general needs. If you would like to develop areas such as DBA, this only the first step is the Great Wall. On the technology I usually defined as: Introduction, understanding, familiar, proficient. China is now the vast majority of PG (certainly including me) Department and the entry and understanding risk. Really hope you were home later on in the near future we can in this regard over India, to catch up with America.

Oracle Introduction (1) must know the technical terms

1: SQL (Structured Query Language) query structure.

2: something (Transaction): refers to as a single logical unit of work performed a series of operations. And the transaction must have four characteristics:

<1>: atomic (atomic): transaction must be atomic unit of work; for its data changes, or all of the implementation or not implementation of the whole.
<2>: consistency (consistent): a transaction is completed, all data must have maintained a consistent state.

<3>: isolation (insulation): the transaction by the concurrent changes to be made with any other concurrent transactions modify the isolation

<4>: Persistence (Duration): transaction is complete, it is for the system of permanent

2: DML, DDL, DCL, TCL operations (division by SQL functions):
(1): Database Manipulation Language: DML (Data Manipulation Language) - include: SELECT, INSERT, UPDATE, DELETE,
(2): database definition statements: DDL (Data Definition Language) - including: CREATE, ALTER, DROP, TRUNCATE,
(3): Database control statements: DCL (Data Control Language) - include: GRANT, REVOKE
(4): transaction control statements: TCL (Transaction Control) - including: COMMIT, SAVEPOINT, ROLLBACK,
SET TRANSACTION. (Some books included in DML operation will operate within the TCL).

3: database storage structure: physical and logical storage structure storage structure.
(1): the physical storage structure consists of: <1> extension. DBF data files (Data File);
<2> extension>. LOG log file (Redo Log File);
<3> extension. CTL in the control file (Control File);

(2): Logical Storage Structure: Database block (DATA BLOCKS), panel (EXTENT), paragraph (SEGMENT), table space (TABLE SPACES).

Database block: Oracle used to manage the most basic unit of storage space is the smallest logical storage unit.

Panel: a series of contiguous blocks on the physical form of the storage structure, which is the smallest disk unit.

Section: is an independent logical storage structure, according to characteristics can be divided into: data segment, index segment, rollback segment, LOB segment, temporary segment.

Table space: ORACLE user can use the maximum logical storage structure.

4: Memory Architecture (SGA).

SGA structure:

Redo log buffer high-speed data buffer large shared pool shared pool (optional)

Other data dictionary data buffer buffer

5: Oracle instance (instance): the memory and the process of regional cooperation as an Oracle instance. The same process can be divided into single and multi-process instance will be practical (MTS).

6: Data Dictionary (DATA DICTIONARY) by Oracle in a series of cases of read-only form the basis of the table and view and save all the basic information on the image.

7: Paradigm (normal form) theory: 1NF, 2NF3NF, BCNF

The first paradigm (1NF): The most simple definition is no repeat of the column.

The second paradigm (2NF): a simple definition is entirely dependent on the primary key attribute.

The third paradigm (3NF): a simple definition is that property is not dependent on other non-primary attributes.

BCNF paradigm (BCNF): 3NF changes, the simple definition does not depend on non-trivial function of the main property.

This argument may have some colleagues in addition to the first, second paradigm to understand things, 3NF, BCNF can not understand the book to see what the actual examples. Personally feel that as long as the master 1NF, and 2NF enough. In practice very few projects to achieve 3NF and BCNF, and in practice we often sacrifice the pursuit of storage space away DML operation efficiency and convenience.

8: dirty (gray) data block (Dirty data block)

Stored in the memory of the original data has been modified, and modified data not yet written to the database.

9: hot data block (Hot data block)

Store the modified data, who are often called hot data block.

10: a database of basic data such as (Data Object): tables, views, sequences, synonyms, triggers, database links and packages, procedures and functions

(1): Table (Table) - DB basic data storage structure.

(2): View (View) - the view is stored in a database query SQL statement, he causes: For security reasons, the view can hide some of the data

(3): Sequence (Sequence) - the only digital out is used to create the database objects, sequences created with the initial value, increment value, maximum value and so on up to 38 integer

(4): synonym (synonym) - refers to other database tables of the database pointer. He has two types: private (private) and public (public). Private synonym is created in the specified mode and only create access to use the model. Public synonyms are specified by the mode of public access to all database schema (user) can access it.

(5): the trigger (trigger) - a special stored procedure, its implementation is not called by the program, not manually start, but by one event to trigger (such as the DML operation)

(6): Database chain and package (database link) - is connected with the remote database storage definition for the check were distributed database environment for remote

(7): Process (Procedure) - is a PL / SQL block, it is stored in the data dictionary application can be invoked, the benefits of using stored procedures is to implement a data security. Authorized users can not direct the application of some form, while the authorized user to perform a process these tables.

(8): function (Function) - and the process, the function also has a parameter, is stored in a database block. The difference is that function can return the value to the caller, you can call them in the SQL statement.

These are the professionals we often hear the term, learning Oracle we have to know the people say "Segment, DDL operations such as" What is meant, to not give a very amateur feel. The following so we can remember to remember, as long as the class of people than some DBA work on, generally will not use:

Database write (DBW0 or DBWn); log written (LGWR); detection point (CKPT); system monitor (SMON); process monitor (PMON); archive (ARCn); recovery (RECO); lock (LCK0); work queue ( SNPn); queue monitor (QMNn); release (Dispatcher Dnnn) server (Snnn); dirty area (Dirty Buffers); Free Zone (Free Buffers); Free Zone (Free Buffers); Reserve (Pinned Buffers) ... ...

分类:Tech 时间:2010-04-07 人气:202
blog comments powered by Disqus


  • MS SQL Server Query Optimization 2010-06-09

    MS SQL Server Query Optimization Study: xmllover 2007-11-29 Query slow for many reasons, as several common 1, no index or index is not used (this is the most common problems slow query is programming defects) 2, I / O throughput is small, the formati

  • PL / SQL, Advanced Query 2011-09-22

    PL / SQL, Advanced Query 1 With clause 1.1 Learning Objectives Master with clause usage, and understand with clause can improve the query efficiency reasons. 1.2 With clause points 1. With the return clause, the result is stored to the user's tempora

  • In Sql Server query statement can not be expressed with variable table name 2010-09-02

    Description: This is the query in the Sql Server can use the variable in that table name - MS-SQL Server / base class details page, introduced and mssql, in Sql Server query statement can not be expressed with variable table name - MS- SQL Server / b

  • SQL Server index structure and its use (II) 2011-06-01

    Improve SQL statement Many people do not know the SQL statements in SQL SERVER is how to implement, they are worried about their own written SQL SERVER SQL statement will be misinterpreted. For example: select * from table1 where name=''zhangsan'' an

  • SQL fuzzy query syntax LIKE 2010-04-10

    SQL fuzzy query syntax LIKE (Tags: Zatan Category: Software Programming SQL fuzzy queries related to the implementation of a database query, a complete query and fuzzy query distinction. General fu

  • [Change] sql: recursive query Xiangjie 2010-02-05

    This paper introduces Oracle's recursive query syntax, use this syntax, you can easily achieve the two-way recursive query: - Tirle: Recursion query for TREE with "connect by / start with" - Author: - Create Date: - Version: - Last Modify: Direc

  • [Reprinted] Oracle built-in SQL functions - sorting Daquan 2010-03-02

    Oracle built-in SQL functions - sorting Daquan F.1 Character Functions - return character value These functions are all family received a character type parameter (CHR excluded) and the return character value. In addition to the special note, the maj

  • SQL Server index structure and its use (C) 2011-06-01

    Small amount of data to achieve a common page and display massive data storage process Build a Web application, tabbed browsing is essential. This problem is very common in database processing problems. The data page is classic: ADO record set paging

  • Console version of the SQL Server Query Analyzer 2010-06-19

    SQL Server Query Analyzer on the use of its internal operating mechanism can have a preliminary understanding; combined system on the Enterprise Manager that comes with the analysis of some documents, the user's operating results are reflected in one

  • sql server 2000 change database name. change the logical file name! 2010-09-24

    sql server 2000 change database name, change the logical file name 2010-09-24 11:00:00. One. Change the database physical file name in Enterprise Manager can not directly change to run in Query Analyzer (database name): the original name of the datab

iOS 开发

Android 开发

Python 开发



PHP 开发

Ruby 开发






Javascript 开发

.NET 开发



Copyright (C), All Rights Reserved. 版权所有 黔ICP备15002463号-1

processed in 0.635 (s). 10 q(s)