Cracking the coding interview: 189 programming questions and solutions 6th edition
Databases
2.1. LEFT OUTER JOIN, or just LEFT JOIN: all records on the left will be in the result
table. If no matching records were found in the correct table, then the
NULL values. In our example, we would get 4 records. In addition to the INNER JOIN results,
BUDWEISER will appear in the list, because it was in the table on the left.
2.2. SONGS RIGHT OUT, or just RIGHT ONE: Reverse joint type is LEFT
Join us; all records will be cracking the coding interview: 189 programming questions and solutions 6th edition from the table on the right and fields will be missing from the table on the left
there is NULL
.
In our example, we get 5 records. In addition to the results of INNER JOIN, FRESCA and WATER
the records will be listed.
2.3. TOTAL ONLY
This join type combines the results of the LEFT join and RIGFHT. All records from both tables
it will be part of the result of the set, whether or not the record matches in the following table. Both of them
In our example, we get 6 records.
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Knowledge Based Coding Interview Scheduling
Denaturation is the process of optimizing the performance of a database by using
adding redundant data or grouping data. In some cases, deregistration helps cover up
inefficiencies inherent in relational database software. Normalized relative database
places a heavy access load on physical data storage, even if it is tightly adjusted
performance.
Standard designs often store different but related information separately
logical tables (called relationships). If these relationships are physically stored as separate disk files,
complete a database query that extracts information from multiple relationships (connect operation)
it can be slow. If enough relationships are required, it may be too late. There are two strategies
gies to deal with this. The best method is to keep the normalized logical layout, but
on disk to optimize the answer to the question. In this case, it is the responsibility of the DBMS software
make sure excessive copies stay consistent. This method is often applied
in SQL as indexed views (Microsoft SQL Server) or relevant views (Oracle). Scene representation
represents information in a format that is convenient for asking questions, and the index ensures that questions are asked
optimized against sight.
The usual approach is to deconstruct the logical data design. With care, this is possible
achieve a similar improvement in the answer to the question, but at a cost: it is now the database
It is the responsibility of the subscriber to ensure that the unsubscribe database does not become inconsistent.
store. This is done by creating rules in the database called constraints, which specify how
Excessive copies of information must be kept in sync. The increase is a logical comparison
The complexity of the database design and the added complexity of additional limitations
this approach can be dangerous. Furthermore, restrictions introduce trade, at a rate
read (SELECT in SQL) and write slowdown (INSERT, UPDATE, and DELETE). This means
a debugging database with a heavy write load might perform worse than
its normalized counterpart is functionally equivalent.
A decentralized data model is not the same as a non-normalized data model,
and deregistration should only take place after a satisfactory level of normalization
occurred and the necessary restrictions and / or rules have been created to deal with them
the underlying design anomalies. For example, all relations are in the third normal form
and any relationship to multiple valuation and join dependencies is handled appropriately.