Sql certified expert exam guide pdf free download

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Report a Bug. Previous Prev. Next Continue. Although options A and B are recommended practices for upgrade performance, option D is a must.

The Pre-Upgrade Information tool must be run, and all errors must be taken care of before upgrading the database. Option C is not required for the upgrade process.

The default is seconds. A lower value will reduce the instance recovery time, but may cause frequent checkpoints. A value of 0 turns off MTTR tuning. Read Chapter 15 for more information. A large pool is configured and is responsible for most of the SGA space allocation. The cache size and block buffers settings do not affect Oracle Shared Server. See Chapter 12 for more information. Recovery options are optional when you create a database.

Read Chapter 9 for more information. Option A is invalid. See Chapter 11 for more information. All uncommitted changes are rolled back, and committed changes are written to data files during instance recovery. LOCAL implies the current machine only. Every database must have at least two redo log files, which may or may not be multiplexed.

Every database must have one control file. It is a good idea to have more than one control file for redundancy. Read Chapter 8 for more information.

There are no standard password complexity settings in either the initialization parameters or profiles. Answers to Assessment Test lxi The shared pool has three components: library cache, result cache, and dictionary cache. You can use the Undo Management Advisor to monitor and manage the undo segments to ensure maximum levels of read consistency and minimize occurrences of ORA Snapshot Too Old error messages.

This parameter is useful to reduce fragmentation in the tablespace. See Chapter 13 for more information. Protocols come with tools that allow you to test network connectivity. The user supplies either an IP address or a hostname to the ping utility.

It then searches the network for this address. If it finds one, it displays information on data that is sent and received and on how quickly it found this address. The other choices are Oracle-supplied utilities. Read Chapter 12 for more information. The online redo log files are used to roll forward after an instance failure; undo data is used to roll back any uncommitted transactions. See Chapter 18 for more information.

However, shared servers do not receive requests directly from dis- patchers. The requests are taken from the request queue. The distance between the checkpoint position in the redo log file and the end of the redo log group can never be more than 90 percent of the size of the smallest redo log group. REPLACE is the valid value; it drops the existing table and creates the table using the definition from the dump file. SKIP leaves the table untouched. Read Chapter 18 to learn more.

Oracle Database 12c uses the Automatic Diagnostic Repository to maintain the alert log and other diagnostic information. Option A is not correct because operations on temporary tablespaces do not gen- erate redo, and a temporary table is created in a temporary tablespace. When DML is performed on a temporary table, the undo is written by default to the active undo tablespace, which generates redo.

Option C is wrong. See Chapter 10 for more information. In the previous database releases, the upgrade script was named catupgrd.

In Oracle Database 12c, the upgrade script is also catupgrd. This script runs the upgrade in parallel by default, thereby reducing the upgrade time.

The utlui. The utlus. The ASM instance does not have any data files or database associated to it; it has only the memory structures and processes.

Organizations and individuals collect and use a variety of infor- mation data. A database collects data, stores and organizes data, and retrieves related data used by a business. With the release of its Database 12c, Oracle has enhanced the capabilities of its feature-rich database to include cloud architecture. The c in 12c stands for cloud computing. From Oracle version 8 onward, Oracle includes the core emphasis of the release along with the version number in its name. Versions 8 and 9 are called i to indicate Internet computing; versions 10 and 11 are called g for grid computing.

With the cloud enablement, Oracle Database 12c lets you manage many databases as one, thereby reducing overhead and valuable resource consumption.

This chapter will introduce you to the Oracle Database 12c high-level components and how the Oracle database is organized. You will also learn about the relational and object capabilities of the database, and the tools available for database administrators DBAs to retrieve information and manage the database. In a DBMS, the kernel code is the software piece that manages the storage and memory component of the database. There is metadata in the DBMS that keeps track of all the com- ponents of the database, also known as the dictionary.

The code or language used to retrieve data from the database is known as SQL, which stands for Structured Query Language. Over the years, database management systems have evolved from hierarchical to network to relational database management systems RDBMS. A relational database management system is an organized model of subjects and characteristics that have relationships among the subjects. A well-designed relational database provides volumes of information about a business or process.

We see relationships everywhere in our daily lives: parents and chil- dren, team and players, doctor and patient, to name a few.

The main advantages of RDBMS include the way it stores and retrieves information and how the data integrity is maintained. RDBMS structures are easy to understand and build. These structures are logically repre- sented using the entity-relationship ER model.

Tables, views, and indexes are examples of structures in Oracle. These rules protect the data and the structure of the database. The primary keys and foreign keys are examples of integrity rules in Oracle. Logical Model In the design phase of the system development cycle, a logical model of the database is created. An ER model has entity, relationship, and attributes. An ER model is visual, showing the structure, characteristics, and interactions within and around the data being modeled.

The characteristics of an entity are known as its attributes. Attributes are detailed information about an entity that serves to qualify, identify, classify, or quantify it. For example: ABC Inc. Placing the organization of ABC Inc. Each entity will also have its own characteristics. See Figure 1. There are optional and mandatory attributes. In Figure 1. An asterisk along with the attribute name indicates that it is mandatory.

The optional attribute may be indicated with a small o. So it is mandatory to have at least one occurrence of department for each location. There may be many departments in one location. Optional occurrence is represented by a dotted line. You should be able to identify each occurrence of an entity uniquely. Now what happens if there are two employees with the same name?

How do you distinguish them? For office location, the city and state uniquely identify each office; for department, the department name identifies it uniquely. For employee, you can introduce a unique identifier UID called employee number. Figure 1. UID is represented in the diagram using a pound symbol. F igur e 1. For example, product and patent—one product might have a patent, and one patent corresponds to only one product.

Many-to-many relationships should not exist in RDBMS because they cannot be properly joined to represent a single row correctly. To solve this, create another entity that has an one-to-many relationship with the first entity and an one-to-many relationship with the second entity. For example, doctor and patient—a patient can visit many doctors, and a doctor can have many patients. They are the common ways you usually query the database in order to retreive information.

Think of the access paths as an index to the data; they help us locate data just as the index of a book helps us quickly find the information we need.

Normalization is the process of eliminating redundant information from the entities until you can uniquely identify each occurrence of the entity. This may not always be practical due to performance and implementation issues. In such cases, you can denor- malize to some extent. Physical Model The physical model is created by taking the logical model and creating a database and data- base objects to represent the entities and relationships. In the physical model, each entity becomes a table and attributes of the entity become columns of the table.

The relationship between the entities is part of one or more constraints between the tables. Physical implemen- tations might force you to combine, separate, or create completely new entities in order to best realize the logical model. The unique identifiers of an entity become the primary key of the table. Stored procedures, functions, and triggers may be created to enforce business rules.

An Oracle database satisfies all three major characteristics of the relational model. Oracle lets you define tables, columns, column characteristics such as datatype, length, whether the values are mandatory, and default values. Defining foreign key ensures the referential integrity of the data.

You can define primary keys and indexes on the data. The primary key of a relational table uniquely identifies each record in the table; it may consist of a single attribute column or multiple attributes in combination.

A foreign key is a column or collection of columns in one table that uniquely identifies a row of another table, defining the relationship between the tables. Records in a database table can be seen as instances of the entity.

Each occurrence of an entity is differentiated by the values of the attributes. Oracle stores these records as rows of the table and the attributes as columns in each row. In the most generic form, a database table can be seen as a single spreadsheet with unlimited numbers of columns and rows. The columns are not defined until the user names them and gives them a datatype.

Oracle extends the concept of spreadsheets by defining relationships between multiple spreadsheets, constraints on columns, and providing mechanisms for multiple users to access the same database table s at the same time. The data access path is implemented in Oracle using indexes. Indexing allows us to predefine to the relational database system the most common access paths that will be used. These indexes decrease the time required to search for data in a table using a number of algorithms such as B-tree, bitmap, etc.

It lets you create user-defined object types in the relational database system. Object types are structures that consist of built-in or user-defined data types. For example, Address can be defined as an object type and can be referenced in tables.

This is a small example to show you how objects can be reused and how the functionality of the RDBMS can be extended to include built-in complex business rules. In this section, we will discuss the capabilities and features of Oracle Database 12c. Detailed architecture and components are discussed in various chapters in Part II of this book.

The physical structure of an Oracle Database 12c server consists of two major compo- nents: the database and the instance. The database is a set of physical files saved on the disk that store information. The instance is a set of memory structures and processes that uses the physical components to manipulate and retrieve data.

The host machine is where the Oracle instance is running. It has the memory structures and processes. The storage array, or disk, is where the database resides. The host machine is where users and applications connect and interact. If the machine goes down for some reason, the database will be unavailable.

In this architecture, more than one instance com- municates to a single database. Oracle RAC takes reliability a step further by removing the database server as a single point of failure. If an instance fails, the remaining instances in the RAC pool remain open and active; and connections from failed instances can be failed-over to active instances. The RAC load balancer directs the user connection request to the appro- priate instance.

Oracle manages the connection load balancing and failover automatically. Many organizations have several hundreds or thousands of Oracle databases. Imagine if the policy were to have one instance per server, then you would have as many servers as the number of instances to manage. If you have a high-capacity server or if the database resource requirements are minimal, you can have more than one instance on the same host machine.

The Oracle Database 12c 11 F igur e 1. You need instance memory structures, processes, and management activities such as backup for each instance or database. With Oracle 12c, a new architecture feature is introduced known as the multitenant archi- tecture. The multitenant architecture enables an Oracle database to function as a multitenant container database CDB that includes zero, one, or many pluggable databases PDBs.

All databases created prior to Oracle Database 12c are non-CDB; a pluggable database appears as a non-CDB to the application, so existing code and application need not be changed when you move to Oracle Database 12c. Oracle RDBMS is responsible for keeping the pluggable databases separate, private for the application, and secure.

The instance and SGA are assigned to a container database. The databases that are part of the CDB are known as pluggable databases. There is no need to change application code or architecture to start using Oracle Database 12c. This drastically reduces the administrative time required. With container and pluggable databases, you only need to back up one multitenant container database. This is especially useful if you plan to upgrade all but a few data- bases to the next release.

Before upgrading the container database, you may move a few pluggable databases to another container database, or move pluggable databases to another CDB of higher release. In the next section, you will learn about users and schema in the database, which is the basis for connecting to the database. Connecting to Oracle Database Before you can connect to an Oracle database, you must create a user.

When you create a new Oracle database, several default users are automatically created. Using this account for day-to-day operations is not recommended. You connect to SYS to start and stop database and other key administrative tasks.

Along with SYS and SYSTEM, several other database users are also created based on the options you choose during the installation and on the components installed in the database. In a container database, the users are either common or local. Common users are visible on the container as well as in all pluggable databases; they have the same username and pass- word across all pluggable databases and in the container database.

The schema for common user is still local to each pluggable database and the container database. A schema is a collection of database objects owned by a user account in the database. The objects in the schema may be related to support a business application. A schema and user have a one-to-one relationship in a database. A schema is created as a user in the data- base, but when the user owns database objects, it is called a schema.

This is known as object-level privilege. For certain users, you may want to grant privileges on all the objects in the database; this is accomplished by using the system privileges. Database Management Tools Oracle Database 12c comes with multiple feature-rich tools to help administrators manage and monitor the database and all of its components. In this section, you will review the tools that are used for everyday administration of Oracle database.

It has several predefined menu functions; therefore, there is no need to remember the syntax or SQL command to perform basic functions. For Linux, you must download and install it outside of an Oracle Database 12c installation. The distribution usually included in the database software distribution might not be the current version. To get started and learn more about SQL Developer, click the choices available in the screen.

The section marked 1 shows various database connections and the objects in those data- bases. Section 2 provides you with a set of predefined reports. If you know how to write SQL, you can define your own reports as well. Section 4 is the SQL worksheet. You use this section to interact directly with the data- base using SQL language.

Output from the SQL commands is listed in section 5; both query output and script output are visible. Section 6 is the logging pane. This is useful when you are debugging code. You run SQL commands to query the database or to manage the database. This tool is automatically installed when you install the Oracle Database 12c server software.

The connect string following is the database alias name known as the net service name. If you omit the password, you will be prompted to enter it. The Oracle Database 12c 17 F igur e 1. Type the command you want to execute at this prompt. You can also format query results and perform calculations.

On platforms where a return code is used, you can provide a return code while exiting. You can also use the QUIT command to complete the session. They are discussed in this book in various chapters.

OEM Database Express is designed to manage only one database, and is intended for database administrators. When you invoke Database Express, you will be prompted for a username and password to connect to the database. You should provide a user account that has administrative privileges. For the SQL section of this book, you will not be using this tool, so we will not discuss it in more detail here.

With OEM 12c, you can manage multiple databases and all products under the Oracle stack. It is a complete cloud lifecycle management answer to quickly set up, administer, and support enterprise clouds and Oracle environments from applications to storage.

OEM 12c is not part of the Oracle Database 12c software install; it must be downloaded and installed separately. Cloud resources are shared not only by multiple users, but are also capable of reallocation based on demand. Cloud computing allows organizations to provision resources and applications rapidly, with improved manageability and less administrative overhead.

By enabling customers to efficiently use their information technology infrastruc- ture, Oracle Database 12c was designed for the cloud. DBAs need to perform fewer patches and upgrades and will not need to configure many backups. The heat map fea- ture tracks data usage information; administrators can create appropriate policies to automatically move and compress data based on age and activity of data.

Oracle Database 12c helps customers reduce IT complexity and cost through private data- base cloud deployments by consolidation. Cloud computing offers an opportunity for IT orga- nizations to be more responsive to changes in application workloads and business demands.

You can use the RUN command instead of a slash to execute a statement in the buffer. The SQL prompt returns when the statement has completed execution. You can enter your next command at the prompt. When you continue a SQL command to the next line, a line number appears at the beginning of the line.

This is in contrast to SQL statements, which can be continued to the next line without a continuation operator. Invisible columns are newly introduced in Oracle Database 12c, where a column in the table can be hidden from the application. Invisible columns help to remove a column from the table quickly without actually dropping the column. Invisible columns are discussed in Chapter 7. You can run the command in this buffer again by simply typing a slash or using the RUN command. You do not need to type the entire SQL statement again.

Instead, just edit the existing statement in the buffer. Please confirm exact pricing with the exam provider before registering to take an exam. After the retirement date, please refer to the related certification for exam requirements. Skip to main content.

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