a0126 oracle database 10g ocp certification all in one exam guid morebook vn 6482

All-in-1 / Oracle Database 10g OCP Certification All-in-One / Watson & Bersinic / 5790-3 /Chapter blind folio: P PART I Oracle Database 10g Administrative I Exam ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ch01.indd Chapter Chapter Chapter Chapter Chapter Chapter Chapter Chapter Chapter Chapter 10 Chapter 11 Chapter 12 Chapter 13 Chapter 14 Chapter 15 Chapter 16 Chapter 17 Chapter 18 Chapter 19 Chapter 20 Chapter21 Basic Oracle Concepts Installing Oracle Database 10g Creating an Oracle Database Interfacing with the Oracle Database Managing Oracle Processes Managing Oracle Storage Structures Administering Users Managing Database Objects Manipulating Database Data Programming Oracle with PL/SQL Securing the Database Configuring Oracle Networking Managing Shared Servers Managing Database Performance Monitoring Oracle Managing Undo Dealing with Locking Configuring the Database for Backup and Recovery Backing Up Oracle Databases Recovering Oracle Databases Managing Globalization in Oracle Databases 6/17/2005 4:39:32 PM All-in-1 / Oracle Database 10g Certification All-in-One / Meyers / 5790-3 / Chapter 23 blind folio: PB ch01.indd 6/17/2005 4:39:57 PM All-in-1 / Oracle All-in-1 Database / Oracle10g Database OCP Certification 10g Certification / Watson All-in-One & Bersinic / Meyers / 5790-3 / 5790-3 /Chapter / FM blind folio: PB CHAPTER Basic Oracle Concepts In this chapter you will learn • What a database is and what makes a database relational • What SQL is • Which database objects are supported in Oracle 10g • What a database administrator does • How the Oracle database fits into the Oracle product family ch01.indd 6/17/2005 4:39:58 PM All-in-1 / Oracle Database 10g Certification All-in-One / Meyers / 5790-3 /Chapter 23 Oracle Database 10g OCP Certification All-in-One Exam Guide Someone once said that the best place to start is at the beginning With Oracle, that means understanding where the idea of a relational database management system (RDBMS) came from and what a database is—in computer and everyday terms Even though the material presented here may not be directly tested on the exam, this is assumed knowledge, however, so a quick read is probably a good idea Introduction to Databases and the Relational Model In one form or another, databases have always been around, though their exact shape was not always easily recognizable As long as some form of data had to be stored, there was always a method of storing it Databases, in their most simple form, are a mechanism for storing data The data can be logical, like the values stored in a computer program, or may be physical, like a file or receipt You probably have databases in existence all around you, but you may not see them as such For example, the shoebox in which you’ve placed your tax receipts for the accountant is a database of your annual expenses When you open a file cabinet and take out a folder, you are accessing a database The content of the file folder is your data (e.g., your credit card statements, your bank statements, invoices, purchase orders, etc.) The file cabinet and drawers are your data storage mechanisms Before the advent of computers, all data was stored in some easily recognizable physical form The introduction of computers simply changed the data from a physical form that you can touch and feel to a digital form that is represented by a series of 1’s and 0’s Does the information that you display for an expense report on the computer screen differ greatly from the same information in the hard-copy version of the expense form? Perhaps the information is laid out differently than on the screen, but the key elements—who was paid, what amount, how much was the tax, what was the purpose of the expense, and so on—are all the same In looking at a database and its most basic set of characteristics, the following points hold true: • A database stores data The storage of data can take a physical form, such as a filing cabinet or a shoebox • Data is composed of logical units of information that have some form of connection to each other For example, a genealogical database stores information on people as they are related to each other (parents, children, etc.) • A database management system (DBMS) provides a method to easily retrieve, add, modify, or remove data This can be a series of filing cabinets that are properly indexed, making it easy to find and change what you need, or a computer program that performs the same function ch01.indd 6/17/2005 4:39:58 PM All-in-1 / Oracle Database 10g OCP Certification All-in-One / Watson & Bersinic / 5790-3 /Chapter PB Chapter 1: Basic Oracle Concepts PART I When data began to move from a physical form to a logical form using computers, different theoretical versions of systems to manage data evolved Some of the more common database management systems in use over the last 50 years include the hierarchical, network, and relational Oracle is a relational database management system (RDBMS) The Relational Model of Databases The relational model for database management systems was proposed in the June 1970 issue of Communications of the ACM—the Association of Computing Machinery journal—by Dr E.F Codd, an IBM researcher, in a paper called “A Relational Model of Data for Large Shared Data Banks.” For its time it was a radical departure from established principles because it stated that tables that have related data need not know where the related information is physically stored Unlike previous database models, including the hierarchical and network models, which used the physical location of a record to relate information between two sets of data, the relational model stated that data in one table needed to know only the name of the other table and the value on which it is related It was not necessary for data in one table to keep track of the physical storage location of the related information in another NOTE The full text of Dr E.F Codd’s paper “A Relational Model of Data for Large Shared Data Banks” can be found in the classics section of the ACM web site at www.acm.org/classics/nov95/toc.html The relational model broke all data down into collections of objects or relations that store the actual data (i.e., tables) It also introduced a set of operators to act on the related objects to produce other objects (i.e., join conditions to produce a new result set) Finally, the model proposed that a set of elements should exist to ensure data integrity so that the data would be consistent and accurate (i.e., constraints) Codd proposed a set of twelve rules that would allow designers to determine if the database management system satisfied the requirements of the relational model Although no database today satisfies all twelve rules (because the database would run very slowly if it did, since theory is not always the same as practice), it is generally accepted that any RDBMS should comply with most of them The essence of the relational model is that data is made up of a set of relations These relations are implemented as two-dimensional tables with rows and columns as shown in Figure 1-1 In this example, the Customers table stores information about clients we deal with—their customer ID, their company name, their address, and so on The Orders table stores information about the client orders (but not the order line items—these are in another table), including the order data, the method of payment, the order date, and the ship date The CustomerID column in both tables provides the relationship between the two tables and is the source of the relation The tables themselves are stored in a database that resides on a computer The physical locations of the tables need not be known—only their names ch01.indd 6/17/2005 4:39:58 PM All-in-1 / Oracle Database 10g OCP Certification All-in-One / Watson, Bersinic / 5790-3 Glossary of Acronyms RAID Redundant Array of Inexpensive Disks Techniques for enhancing performance and/or fault tolerance by using a volume manager to present a number of physical disks to the operating system as a single logical disk RAM Random Access Memory The chips that make up the real memory in your computer hardware, as against the virtual memory presented to software by the operating system RDBMS Relational Database Management System, often used interchangeably with DBMS RMAN Recovery Manager Oracle’s backup and recovery tool RVWR The Recovery Writer background process, an optional process responsible for flushing the flashback buffer to the flashback logs SBT System Backup to Tape An RMAN term for a tape device SCN System Change Number The continually incrementing number used to track the sequence and exact time of all events within a database SGA System Global Area The block of shared memory that contains the memory structures that make up an Oracle instance SID System Identifier The name of an instance, which must be unique on the computer the instance is running on (2) Session Identifier The number used to identify uniquely a session logged on to an Oracle instance SMON The System Monitor The background process responsible for opening a database and monitoring the instance SQL Structured Query Language An international standard language for extracting data from and manipulating data in relational databases SSL Secure Sockets Layer A standard for securing data transmission, using encryption, checksumming, and digital certificates TCP Transmission Control Protocol Together with the Internet Protocol, TCP/IP, the de facto standard communication protocol used for client/server communication over a network TCPS TCP with SSL The secure sockets version of TCP TNS Transparent Network Substrate The heart of Oracle Net, a proprietary layered protocol running on top of whatever underlying network transport protocol you choose to use, probably TCP/IP UGA User Global Area The part of the PGA that is stored in the SGA for sessions running through shared servers glossary.indd 7/12/2005 9:54:15 AM All-in-1 / Oracle Database 10g OCP Certification All-in-One / Watson, Bersinic / 5790-3 Oracle Database 10g OCP Certification All-in-One Exam Guide UI User Interface The layer of an application that communicates with end users, nowadays frequently graphical: a GUI URL Uniform Resource Locator A standard for specifying the location of an object on the Internet, consisting of a protocol; a host name and domain; an IP port number; a path and filename; and a series of parameters UTC Coordinated Universal Time, previously known as Greenwich Mean Time (GMT) UTC is the global standard time zone; all others relate to it as offsets, ahead or behind X As in X Window System, the standard GUI environment used on most computers, except those that run Microsoft Windows XML Extensible Markup Language A standard for data interchange using documents, where the format of the data is defined by tags within the document glossary.indd 7/12/2005 9:54:15 AM .. .All- in- 1 / Oracle Database 10g Certification All- in- One / Meyers / 5790-3 / Chapter 23 blind folio: PB ch01.indd 6/17/2005 4:39:57 PM All- in- 1 / Oracle All- in- 1 Database / Oracle1 0g Database. .. the Oracle product family ch01.indd 6/17/2005 4:39:58 PM All- in- 1 / Oracle Database 10g Certification All- in- One / Meyers / 5790-3 /Chapter 23 Oracle Database 10g OCP Certification All- in- One Exam. .. stored in the SGA for sessions running through shared servers glossary.indd 7/12/2005 9:54:15 AM All- in- 1 / Oracle Database 10g OCP Certification All- in- One / Watson, Bersinic / 5790-3 Oracle Database