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Explain several types of constraints that can be specified using CREATE TABLE command. Explain CASCADE and RESTRICT clauses of DROP SCHEMA command?Constraint DescriptionPRIMARY KEY Determines that column(s) uniquely identifies each record. The primary key cannot be NULL, and the data value(s) must be unique.
FOREIGN KEY In a one-to-many relationship, the constraint is added to the "many" table. The constraint ensures which if a value is entered into a specified column, it must already exist in the "one" table, or the record is not added.
UNIQUE Ensures that all data values stored in a specified column are unique.The UNIQUE constraint differs from the PRIMARY KEY constraint in which it permits NULL values.CHECK Ensures in which a specified condition is true before the data value is added to a table. For example, an order's ship date cannot be previous than its order date.
NOT NULL Ensures in which a specified column cannon contain a NULL value. The NOT NULL constraint can just be created along with the column-level approach to table creation.
Prevents the DROP from taking place if any dependent objects exists (RESTRICT) or causes all dependent objects do also be dropped (CASCADE).
Need for Multiple Access Paths In practice, most of the online information systems need the support of multi-key files. For example, consider a banking database application hav
Define Deadlock prevention These protocols make sure that the system will never enter a deadlock state. There are two methods to deadlock prevention. One approach makes sure t
Can a domain, assigned to a data element be changed? Yes. We can do so by just overwriting the entry in the field domain.
What is Management System? A management system is a set of rules and process which help us to create organize and manipulate the database. It also helps us to add, change delet
Compute the closure (F+) for the following set of the functional dependencies defined on R(a,b,c,d), where F - {c→ a, ab → d, a → b, d → c}, i.e. what are all of the FDs implied b
A database is to be constructed to remain track of the teams and games of a sport league. A team has a number of players, not all of whom participate in every game. It is desired
#quCreate a database design specification (Enhanced Entity Relationship Diagram (EERD) and Relational Data Model (RDM)) from the given business description. The RDM must be in 3rd
Define the phases of two phase locking protocol Growing phase: a transaction may get locks but not release any lock. Shrinking phase: a transaction might be release locks bu
Submit SQL INSERT Statements that will populate the database with sample data. You must insert at least 5 records into each table in your database.Submit your SQL INSERT Statement
Design an algorithm to implement operations Each and every operation specified in the functional model could be formulated as an algorithm. The algorithm indicates how operat
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