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Explain Record Based Logical Models?
Record-Based logical Models: Also define data at the conceptual and view levels. Unlike object-oriented models, are used to state overall logical structure of the database, and gives a higher-level description of the implementation. Named so since the database is structured in fixed-format records of various types. Each record type defines a fixed number of fields, or attributes. Each field is commonly of a fixed length (this simplifies the implementation). Record-based models do not involved a mechanism for direct representation of code in the database. Separate languages related along with the model are used to express database queries and updates. The three most widely-accepted models are the relational, network, and hierarchical.
What is meant by functional dependencies? Consider a relation schema R and α C R and β C R. The functional dependency α ->β holds on relational schema R if in any legal relati
construct a B+ tree for the following set of key value (2,3,5,7,11,19,23,29,31) in ascending order where the pointers that will fit in one node is as follows:A. four B. six C. eigh
I have to create a database about anything of my choice. It has to contain 4 queries, and 4 forms. It can be anything as simple as a shoe inventory with numbers - is this a service
Compare wait-die deadlock prevention scheme with wait-wound scheme Ans: Wait-Die Scheme a) Based upon a nonpreemptive technique. b) If Pi requests a resource present
Q. Define a weak entity set and its identifying relationship. List the necessary conditions for a meaningful identifying relationship set of a weak entity set. Entity is a t
Primary index A primary index is a file that has a sorted series of records having two columns: a block address for that key field in the data file; and the ordering key field.
Describe the functions and features of foreign key? Foreign Key : The primary key of one file or table that is implanted in another file or table to implement the relationships
Explain the two types of participation constraint. 1. Total: The participation of an entity set E in a relationship set R is said to be total if each entity in E participates i
define attribute inheritance with example?
Explain Dynamic Two-Phase Locking Here a transaction locks a data item instantly earlier than any operation is applied on the data item. After finishing all the operations on
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