Concise Guide to Databases: A Practical Introduction (Undergraduate Topics in Computer Science)
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This easy-to-read textbook/reference presents a comprehensive introduction to databases, opening with a concise history of databases and of data as an organisational asset. As relational database management systems are no longer the only database solution, the book takes a wider view of database technology, encompassing big data, NoSQL, object and object-relational and in-memory databases. The text also examines the issues of scalability, availability, performance and security encountered when building and running a database in the real world. Topics and features: presents review and discussion questions at the end of each chapter, in addition to skill-building, hands-on exercises; introduces the fundamental concepts and technologies in database systems, placing these in an historic context; describes the challenges faced by database professionals; reviews the use of a variety of database types in business environments; discusses areas for further research within this fast-moving domain.
Process will even out the load across the users. Another RDBMS background process is a process manager. This constantly checks to make sure that all open connections, with their associated server sessions, are active. Any timed-out sessions are killed by this monitor, since every connection takes some resource, even if it isn’t active, thus affecting overall performance. 11.3.6 Archive Manager As we have seen elsewhere there are often conflicting needs that a DBA needs to balance. Availability.
Of the smaller table and performs a hash algorithm on the columns for the joined columns and then stores the result. It then iterates through the rows of the other table performing the same hashing algorithm on the joined columns. It then compares with the first result and if they match it returns the row. Once the rows are output Oracle sorts. Because it has estimated how many rows will be output it also suggests it will need 15 Mb of Temporary Space to perform the sort. Note that the estimated.
Interact with a modern database system by using logical concepts such as tables and rows, and so we also explain how physical storage can map to logical objects. Database professionals deal with data on a daily basis. We look at the ways that this raw material can be moved between disparate systems using tools like SQL Loader and Import/Expotr. In addition we look at how professionals can use the supporting files, such as redo logs and alert logs. Finally we discuss placement of the data, and.
Straightforward Read Before we go any further, let us see how a request for some information might be treated in the RDBMS. In the process we will come across other structures which we will review in detail afterwards, but, for now, let’s concentrate on the overall operation. Our user, called User_A, needs to know the address of one of their customers. They may well write something like: Select Surname, Firstname, address1, address2, address3, city, county, nation, telephone From Customers.
Shop_customer_ty AS OBJECT (customer_no varchar(9), name varchar2(25), address addr_ty); Obviously you must create something before you can use it in another creation statement so in this example you must create the address type first before you can use it in the shop customer type. Once you have created a type you can use it multiple times, for example address is used in purchase order. Up until this stage the structure looks object oriented but actual data still needs to be.