Database for information systems Describe the transformation process from an ERM
ID: 3867400 • Letter: D
Question
Database for information systems
Describe the transformation process from an ERM to database implementation Discuss the phrase. "A database at implementation phase consists of only 1: M relationships" Should tables without any relationship to other tables should remain in the database. If not what should be done? Describe the data types and constraints that are used in your working DBMS. Using desk research identifies some good quality practices that will prevent erroneous data entry. Describe the database ON DELETE and ON UPDATE constraints ensure referential integrityExplanation / Answer
2)The implementation phase DBMS is a phhase that where we kept database on the required hardware,and load the data. Initially the data could be either new data captured or existing data imported. And also we need to establish database security in this phase and providing applicable accesses to users.
3)There is no certainly required for all tables of database sould be in relationship, but it's bad idea of maintaining tables without relation to other.
4) The data type is nothing but a type of label to understand what type of data is expected inside column.
CHARACTER :Character of a string.
VARCHAR(n) :Character string with perticular Variable length
BINARY(n) :Binary string
BOOLEAN :TRUE or FALSE
INTEGER :Integer numerical
FLOAT(p) :Approximate numerical
DATE : used to store year, month, and day values
TIME :For time hours, minute, and second values
CONSTRAINT is nothing but an integrity to define some conditions to restrict the attributes that they should remain true while modifying tables.The following are the sql constraints.
NOT NULL :It confirms that a column cannot store NULL value.
UNIQUE :It ensures that each row must have a different value.
PRIMARY KEY :The main teme of tis constratin is that it is a combination of both NOT NULL and UNIQUE constraints.
DEFAULT :It provides default value.
FOREIGN KEY :To ensure the referential integrity.
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