Foreword:
It’s the season of gold, silver and silver again, so I’m going to go outside to see the environment and see if I’m worth it, so I submitted a few resumes. This article introduces a company that builds a big data platform for government departments.
The whole experience is divided into the following parts:
First, written test questions:
The topics of this link include: some topics of Vue, database topics, algorithm topics, spring source code and basic concept topics, Mybatis topics, redis topics; the answer is limited to one hour.
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The title of vue: what are the assignment operations of attributes, several priorities of css styles, page layout, concepts and differences between redrawing and rearrangement, triggering events of vue, etc., requiring writing source code.
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The title of the database: a query statement, about deleting duplicate values, only keep the latest one, summary processing of the report (requires deduplication according to the phone number, and summarizes the number of calls, total duration, etc.), clustering index and non-clustering of the database The difference between cluster indexes, several ways to optimize SQL, etc., requires writing SQL.
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The topic of the algorithm: the conceptual logic of recursion, the source code of bubble sort, the source code of recursive query;
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The topic of spring: What is the internal principle of spring application operation? , The concept of IOC, what are the commonly used annotations, as well as the function, the principle of assembly, etc.;
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The topic of Mybatis: What are the ways of using mybatis about paging? , the writing of several field replacement characters of mybatis and the use (#{}, ¥{}, etc.), the advantages and disadvantages of mybatis, etc.;
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The title of redis: two backup methods of redis, the type and advantages of redis, the difference between redis and memcache;
The second part of the interview:
Since this company is a big data platform, the HR who interviewed me asked some questions about database optimization, such as how to write two time differences in SQL statements, and what functions were used (I didn’t answer it at the time, but I thought about it later. The next is Datediff on it).
There are also two tens of millions of databases, how to quickly perform associated queries, for example, if an elderly person passes away, one is the basic information table of the elderly, and the other is the personnel death table; how to perform associated queries to make the efficiency Higher processing; for this problem, I said at the time that if you directly query the two tables for association, if there is no foreign key, the association query will be slower. It is best to use an intermediate table for association, for example, you can build a personnel level table, or directly expand a field on the basic table of the elderly to solve the processing; I also asked about the company's processing method, and Hr explained , query separately according to the personnel information table and personnel death table, and then do the processing in memory (the processing of the extended field is omitted, the processing is simpler, and the database used is ES).
Regarding the realization principle of sub-database and sub-table, what I said at the time was that, for example, the personnel basic information table can be processed by sub-database and sub-table according to the city. There are 32 cities in the country, just go to the corresponding library directly to query in different cities. It is said that the open source framework is used for processing, and the specific logic needs to be configured.
I asked some questions about business trips. Since government enterprises all use their own servers, they are all on the intranet, and business trips are required to solve some practical problems. What is the name of the domestic one used by the relational database, I forgot. I don't usually work overtime, and only work overtime when the project is urgent.
at last:
Regarding this interview experience, I found that some formal companies still need to write some code, or need to prepare some before the interview. Use some questions to deal with the interview, otherwise, it is unrealistic to answer them in a short time. Also, some of the questions are practical empirical questions. I just want to see if I have relevant experience. I don’t feel very good about this interview, so I will organize it this time. Next time we meet again, three golds and four silvers, I still have to try the chance. If you successfully change jobs, you will get 5 more Ws, hahaha