database management

The user used to technique to represent and the store data on a file that is called File organization. These are the various four file organization in the database such as. Sequential file organization Relative file organization Indexed sequential file organization Multi key file organization.

The user retrieves the data by using the query in the data manipulation language provided in the database. The query processor uses the data dictionary to find the structure of the relevant portion in the database.

The database is the collection of interrelated file and the program which allow the user to access data. These are the three views in the database. These are such as. The External view: highest level of abstraction The conceptual view: it is the total of user’s view. Internal view: lowest level...

There are various comparison operators used in it such as =,>, <,!, ! =, etc. Comparison operator allow row retrieval from a table based on the condition specified in the WHERE clause Syntax SELECT column_list FROM table_name WHERE expression1 comparison_operator expression2

IN and NOT in comes in the list operators. The IN operator that allows the selection of values that match any one of the values in the list. Same way the NOT IN operator restricts the selection of values that match any one values in the list. Syntax SELECT column_list FROM table_name WHERE...

The range Operator is used to retrieve data that can be extracted in ranges. The BETWEEN and the NOT BETWEEN are the range operators. The BETWEEN keyword in the WHERE clause specifies an inclusive range to search, whereas the NOT BETWEEN keyword is used to exclude rows from the specified range...

Multiple search condition can be combined by using logical operators. These are three logical operators are using in the database. AND: when all condition true OR: when any condition true NOT: Neutralizes the expression Syntax SELECT column_List FROM table_name WHERE conditional_exporession{...

The SELECT statement is used everywhere in the query with the WHERE statement both are used for the retrieve the information from the database and display it. Syntax SELECT column_list FROM table_name WHERE search_condition where search condition may be any search condition.

The select statement can be used to retrieve the specific columns from the table by specifying the column name from the table. The column name specified in the SELECT statement is separated by the comma. Syntax SELECT column_name1[,column_name2,…..] FROM table_name

The SELECT statement is used to access and retrieve data from a database. The SELECT Statement prompts the server to query a single or multiple tables in the database and return it to the client application. The keyword SELECT, FROM and WHERE make a basic select statement. Syntax...

The DISTINCT Keyword removes duplicate rows from the result, it means it will show the result without any repetition of rows, and by default query return all the records including duplicate. Syntax SELECT[ALL/DISTINCT] column_names FROM table_name WHERE search_condition Where search_condition...

If you want to display the top few rows then use the TOP keyword with the SELECT statement, it will return limited number in the result. Syntax SELECT[TOP n[PERSCENT]] column_name [, column_name…] FROM table_name WHERE search_conditions [ORDER BY[column_name[,column_name….] Where n is the...

If you want to retrieve the data from the database and also display the data in specific order then we use the SELECT statement with the order by clause. Syntax SELECT select_list FROM table_name [ORDER BY column_name/ select_list_number/expression [ASC/DESC][...

A collection of records which are connected with each other in the form of tree, this is Hierarchical model. Each record is collection of attributes. A link is association between two records. In many data organization tree structures occur automatically. Now we will take the example of collage...

Candidate Key : it ensures uniqueness and irreduceability i.e no proper subset of A has the uniqueness property.There could be multiple candidate keys however among those only 1 is choosen as primary key and other becomes alternat3 keys. No null value is allowed in candidate key column. Super...

Functional Dependency: It is an assosiation between the two attributes of the relation such that one attribute is known as determinant and other is known as determined and for each determinant there is one and only one value of determined. For example: A-->B here A is determinant and B is...

Information Rule: states that entire data along with names and column names is represented in the form of table. Access Rule: states that a particular record can be accessed only through the primary key that is used to uniquely identify a row. View Updating Rule: states that any modification...

1.Whether to use Entity Set or Attributes: treating something as attribute state that the entity has only 1 telephone number whereas treating telephone as a separate entity state that the person could have multiple telephones. 2.Whether to use Entity set or Relationshio set: Using relationshio...

Data model is an integrated collection of concept that describes the data, the relationships and the constraints applied on that data.Data model consist of 3 things: Structural part Manipulative part Integrity rules and constraints. The purpose of designing the data model is to make the data...

Parallel DBMS: is the one in which the DBMS is running parallel at each site. There are multiple CPU's and disks for storage in parallel accessing. Advantanges: 1.High throughput and response time. 2.Parallel database is useful for multiuser environment. Distributed DBMS: in which database is...