comparisons with database systems

... single server process with internal multitasking would not be subject to any code sharing difficulties, and a dynamic loading solution might be reconsidered An added difficulty with ADT routines ... collection; a specific type, e.g int, float, boolean, char fixed, i.e any type with fixed length variable, i.e any type with a prescribed varying length format fix-var, i.e fixed or variable type1, ... computation Only a user-defined data type facil-ity allows such customization to occur Current data base systems implement hashing and B-trees as fast access paths for built-in data types Some user-defined

Ngày tải lên: 22/10/2013, 10:15

... Trang 1COP 4710: Database SystemsSpring 2004 Introduction to Database Systems – Part 2 BÀI 2, 1/2 ngày School of Electrical Engineering and ... Roles in the Database Environment Trang 4Database Designers• In large db design projects, we can distinguish between two types of designers: logical database designers and physical database designers ... the database • DML operations usually include the following: – insertion of new data into the database. – modification of data stored in the database. – retrieval of data contained in the database.

Ngày tải lên: 24/12/2013, 12:16

... hold on this data 3 Logical Database Design: A DBMS must be selected to implement the database and to convert the conceptual database design into a database schema within the data Introduction ... object-oriented approach to database design that is emerging as a standard for object-oriented database systems Introduction to Data Modeling (cont.) Trang 8• The database design process can ... Conceptual Database Design: The information gathered in the requirements analysis step is used to develop a high-level description of the data to be stored in the database, along with the constraints

Ngày tải lên: 24/12/2013, 12:16

... COP 4710: Database Systems (Day 5) Page 1 Mark Llewellyn COP 4710: Database Systems Spring 2004 Introduction to Data Modeling – Part 2 BÀI 5, 1 ngày COP 4710: Database Systems Spring 2004 ... Diagram COP 4710: Database Systems (Day 5) UML Class Diagram Page 29 Mark Llewellyn Correspondence of E-R & UML Class Diagrams... address country COP 4710: Database Systems (Day 5) Page ... Diagrams COP 4710: Database Systems. .. manages what tasks • The E-R diagram in the next slide illustrates how aggregation is represented in the E-R model COP 4710: Database Systems (Day 5)

Ngày tải lên: 24/12/2013, 12:16

... Evolution of Database Systems 2 1.1.1 Early Database Management Systems 2 1.1.2 Relational Database Systems 4 1.1.3 Smaller and Smaller Systems 5 1.1.4 Bigger and Bigger Systems ... Database Management Systems The first commercial database management systems appeared in the late 1960's These systems evolved from file systems, which provide some of item (3) above; file systems ... Client-Seruer Systems: Database management systems usually support a client-server architecture, with major database components a t the server and the client used to interface with the user + Future Systems:

Ngày tải lên: 24/12/2013, 12:17

... tuple that has name C Fisher, a street and city that agree with the first tuple, and other attributes ( t i t l e and ear) that agree with the second tuple There is indeed such a tuple; it ... the other schema is: {title, year, length,... i t y ) {theater, t i t l e ) There is a proble~n with this decomposition, concerning the FD t i t l e city + theater There could be current relations ... ~lontrivial multivalued (or functional) dependencies, so they are in 4NF Note that in the relation with schema {name, s t r e e t , c i t y ) , the I\.IVD: Another way to compare the normal forms

Ngày tải lên: 24/12/2013, 12:17

... agree with both these tuples on the attributes they have in common The construction of the joined tuple is suggested by Fig 5.5 R In this example, the first tuple of R successfully pairs with ... in the join R w S, then the result of the pairing is a tuple, called the joined tuple, with one component for each of the attributes in the union of the schemas of R and S The ... ships engaged it1 the battle of Guadalcanal f ) List all the capital ships mentioned in the database. .. tuple t Then the expression on the left has one t , while the expression on

Ngày tải lên: 24/12/2013, 12:17

... keywords database systems The current standard is called SQL-99 or SQL3 Com- mercial systems generally wry from this standard + Data Definition: SQL has statements to declare elements of a database ... character strings However, with the name, we have made the decision t o use a Section 6.1.3) with another string fixed-length string of 30 characters: padding a name out with blanks a t the end ... generation of relational database prototypes 1 Astrahan, 14 h,1 et a]., "System R: a relational approach t o data manage- ment," ACM Trcmsactions on Database Systems 1:2, pp 97-137, 1976

Ngày tải lên: 24/12/2013, 12:17

... distributed databaseaccess Databases and Database Links Each database in a distributed database is distinct from all other databases in the system and has its own global database name Oracle forms a database’s ... Distributed Database Administration Global Database Names and Global Object Names 2-2 Types of Database Links 2-3Private, Public, and Global Database Links 2-3Security Options for Database Links ... intermediate HQ database and indirectly to theSALES database that contains the remote data Trang 23Figure 1–1 An Oracle Distributed Database SystemTRANSACTION Network Application Database Server Database

Ngày tải lên: 17/01/2014, 09:20

... an update is made to the database, the DBMS must be able to verify that the update will not result in an illegal instance with respect to the functional must be designed with a set of schemas which ... be in 3NF but not in BCNF Trang 8• The basic goal of relational database design should be to ensure that every relation in the database is either in 3NF or BCNF update anomalies to make a significant ... Trang 1COP 4710: Database SystemsSchool of Electrical Engineering and Computer Science University of Central Florida

Ngày tải lên: 21/01/2014, 18:20

... COP 4710: Database Systems (Day 12) Page 1 Mark Llewellyn COP 4710: Database Systems Spring 2004 Introduction to Normalization – Part 3 BÀI 12, 1/2 ngày COP 4710: Database Systems Spring ... to: R 1 = (A, B, C, E) with K 1 = K = {AB, AC} R 2 = (C, D) with K 2 = {C} Step 2: R 2 in 3NF. R 1 not in 3NF since AB → B → E Decompose R 1 to: R 11 = (A, B, C) with K 11 = K 1 = K ... (B, E) with K 12 = {B} Step 3: R 2 , R 11 , and R 12 are all in 3NF Step 4: Test for the lossless join property (see next page). 5678" COP 4710: Database Systems

Ngày tải lên: 21/01/2014, 18:20

... Trang 1COP 4710: Database Systems (Day 17) Page 1 Mark LlewellynCOP 4710: Database Systems Spring 2004 Introduction to SQL BÀI 13, 2 ngày COP 4710: Database Systems Spring 2004 Introduction ... to speed on that system with the information in this set of notes Trang 5COP 4710: Database Systems (Day 17) Page 5 Mark LlewellynSQL • SQL is a complete relational database language in the ... view Trang 7COP 4710: Database Systems (Day 17) Page 7 Mark LlewellynThe DDL Component Of SQL • Before you can use a RDMS two tasks must be completed: (1) create the database structure, and

Ngày tải lên: 21/01/2014, 18:20

... Trang 14Joining Database Tables• The ability to combine (join) tables on common attributes is perhaps the most important distinction between a relational database and other types of databases • ... and table C is also related to table A, create only two join conditions: join A with B and B with C Do not join C with A! Trang 17Recursive Joins• An alias can be used to identify the source table ... must be joined with itself, called a recursive join • For example, using the EMPLOYEE table we would like to generate a list of all employees along with the name of their manager Without using

Ngày tải lên: 21/01/2014, 18:20

... Trang 1COP 4710: Database SystemsSchool of Electrical Engineering and Computer Science University of Central Florida ... with r(R) and s(S) then, ∀ σA=a (R * S) ≡ σA=a(R) * S – If constraint information is known, they provide even more information and modification possibilities: • If you know that R(A,B,C,D) with ... optimal performance, but this is rare • Each RDBMS will typically maintain a number of general database access algorithms that implement basic relational operations such as select and join Hybrid

Ngày tải lên: 21/01/2014, 18:20

... This level of indirection within the block offers many of the advantages of logical addresses, without the need for a global map table. 1% can move the record around within the block, and all ... represent objects. Also, modern object-relational database systems allow attributes of pointer type (called references), so even relational systems need the ability to represent pointers in ... mem-addr database address memory address Figure 12.8: The translation table turns database addresses into their equiva- lents in memory To a~oid the cost of translating repeatedly from database

Ngày tải lên: 21/01/2014, 18:20

... b Suppose we have a tuple with a-value A and b-value B, perhaps with other attributes that are not involved in the hash We hash A using a hash function ha associated with attribute n to get four ... points into two parts: those with a-value less than V and those with a-value equal to or greater than V The attributes at different levels of the tree are different, with levels rotating among ... 14.3.2 Treat the problem as a range query with the appropriate range and repeat with a larger range if necessary Suppose we store a file in a kd-tree with n leaves Then the average length of a

Ngày tải lên: 21/01/2014, 18:20

... now consider in detail how transactions interact with the database. There case for database elements that are blocks. It would also be true for database are three address spaces that interact ... a copy of the database Similarly, a nonquiescent dump tries to make a copy of the database that existed when the dump began, but database activity may change many database elements ... transaction have been completed and stored on disk, then any database changes that the transaction may have made to the database are undone, and the database state is restored to what existed prior to

Ngày tải lên: 21/01/2014, 18:20

... Distributed Databases We shall now consider the elements of distributed database systems In a dis- tributed system, there are many, relatively autonomous processors that may participate in database ... Conszstent Database States: Database states that obey xhatever i~nplied or declared constraints the designers inte~lded are called consistent It is essential that operations on the database preserve ... transactions unnecessarily, systems usually use several lock modes, with different rules for each lriode about when a lock can be granted Most common is the system with shared locks for read-only

Ngày tải lên: 26/01/2014, 15:20

... also %rehouse Database 2 Database address 579-580, 582 Database administrator 10 Database element 879, 957 Database management system 1 910 Database programming 1, 15 17 Database schema ... Placing queries in the lattice of views helps design data-cube databases. Some recently developed design tools for data-cube systems start with a set of queries that they regard as typical" ... 910 Database programming 1, 15 17 Database schema See Relational database schema Database state See State, of a database Data-definition language 10 292 See also ODL, Schema Datalog

Ngày tải lên: 26/01/2014, 15:20

... Trang 1Query Processing in RDF/S-based P2PDatabase Systems George Kokkinidis, Lefteris Sidirourgos and Vassilis Christophides Institute of Computer ... actually used by groups of peers in order to deploy hybrid (i.e.,super-peer) and structured P2P database systems Finally, Section 4 discusses related work and Section 5 summarizes ourcontributions ... view-clause) with appropriate resources from the peer’s base according tothe bindings introduced in the from-clause Given the query pattern used inthe from-clause, C5 and C6 are populated with resources

Ngày tải lên: 19/02/2014, 12:20