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Short Note

Briefly describe the two-tier and three-tier architecture. DBMS

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Two-tier Architecture: In the two-tier architecture, the application is partitioned into a component that resides at the client machine and calls the database system functionality at the server machine using query language statements. Application program interface standards like ODBC and JDBC are used for interaction between the client and the server.  Three-tier Architecture: In three-tier … Read more

Describe the data structures implemented by the storage manager.

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Data Structures Implemented by the Storage Manager: The storage manager implements several data structures as part of the physical system implementation. Data Files: It stores the database itself. Data Dictionary: It stores metadata about the structures of the database, in particular schema of the database. Indices: It can provide fast access to data items. It … Read more

In how many ways can database constraints be tested/evaluated? Describe briefly. DBMS

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Database Constraints: Database constraints are like conditions given to the manipulation of values of a field or attribute. Such as, we may limit the values under the payment attribute of a table that its value can never be less than BDT 350. Constraints can be tested as follows, Domain Constraints: Using domain constraints one can … Read more

Describe Data Definition Language (DDL). DBMS

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Data Definition Language (DDL): The specific language used to express the database schema by a set definitions is called Data Definition Language (DDL). The DDL is also used to specify additional properties of the data. Another special type of DDL, called the Data Storage and Definition Language, is used to specify storage and data access … Read more

What are database languages? Describe DML (DBMS)

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Database Language: As whatever we want to be manipulated by computer has to be written using specific language, database is not beyond them. To write or create database management system we use database languages. They are of two types; Data Definition Language (DDL) and Data Manipulation Language (DML). DDL is used to design a database … Read more

What is data model? Describe various data models. DBMS

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Data Model: Data model is the structure of the database, which is a collection of conceptual tools for describing data, data relationships, data semantics and consistency constraints.  The data models can be classified into the following four categories. Relational Model: The relational data model uses a collection of tables to represent both data and the … Read more

What is data abstraction? Describe the levels briefly. DBMS

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Data Abstraction: Different users require different view of the database which is useful and necessary to them. This is data abstraction by which we abstract useful data from a database for a particular type of users to use.  There are 3 levels of data abstraction, those are as follows; Physical Level: The lowest level of … Read more

Briefly describe the disadvantages of file processing system? DBMS

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Disadvantages of File Processing System: Keeping organization information in a file processing system has some disadvantages including the followings, Data Redundancy & Inconsistency: As the files are created by different programmers, there is a huge chance of data redundancy which is responsible for unnecessary storage and access cost. This may also lead to data inconsistency … Read more

Write short notes on the Execution Unit (EU) and the Bus Interface Unit (BIU) in 8086 microprocessors

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internal-architecture-of-8086-microprocessor.

Internal architecture of 8086 microprocessor

If we study the internal architecture of 8086 microprocessor, we can see that it has two major units; Execution Unit (EU) and Bus Interface Unit (BIU). They are dependent and work with each other.

In the following given figure, which is a block diagram of 8086 microprocessor, it can be seen it is internally divided into two separate functional units. These are the Bus Interface Unit (BIU) and the Execution Unit (EU). These two functional units can work simultaneously to increase system speed and hence the throughput. Throughput is a measure of number of instructions executed per unit time.

Below is a short description of these two units.

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