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Ans. The combination of values from multiple columns in the composite primary key must be unique for each row in the table.
A foreign key, on the other hand, is a field or set of fields in one table that refers to the primary key in another table. It establishes a relationship between two tables based on the values of the foreign key and the primary key.
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Ans. The impact of both cases (fixed hashcode or random hashcode for keys) will have same result and that is "unexpected behavior". The very basic need of hashcode in HashMap is to identify the bucket location where to put the key-value pair, and from where it has to be retrieved.
If the hashcode of key object changes every time, the exact location of key-value pair will be calculated different, every time. This way, one object stored in HashMap will be lost forever and there will be very minimum possibility to get it back from map.
For this same reason, key are suggested to be immutable, so that they return a unique and same hashcode each time requested on same key object.
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Ans. With resource pooling and Pay as per use , Bigger companies like Google and Amazon can buy Large physical hardware and employ economy of scale and hence resulting in cost saving for customers.
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Ans. There are multiple types of security GCP provides to every customer. Data, Network, Compute, and Services. Each service have its own security layer and Google provides clients to build as per the GCP best practices like building VPC, IAM, Firewall rules and so on
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Ans. Open the AWS CloudFormation console at https://console.aws.amazon.com/cloudformation . Create a new stack by using one of the following options: Choose Create Stack. This is the only option if you have a currently running stack.
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Ans. Broad question, but if the company need velocity, think about use a NO SQL instead of regular SQL databases.
Also prefers materialized views instead of joins to fetch data quickly.
Regarding the database design, there are very good design tools for professional database (to develop proper indexes and good database design) one of the best is QuickDBD
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