sql interview questions book

The php interview questions collected on the Internet are posted for you in the php tutorial! I. Basic Questions 1. What is object-oriented? What are the main features? A face object is an elegant method to directly map objects and concepts in nature to the program world! Main features: abstraction, inheritance, encapsulation, and Polymorphism 2. What is the diff

queries. of course, you must note that the connection columns of the connected table (the second table) are indexed, in the first table, MySQL usually performs a full table scan relative to the query subset of the second table, which is part of the nested loop algorithm. 5. optimize UNION Using UNION across multiple different databases is an interesting optimization method. UNION returns data from two unrelated tables, which means no duplicate rows will appear, data must also be sorted. we know

. On the first table, MySQL usually does a full table scan relative to the second table's subset of queries, which is part of the nested loop algorithm. 5. Optimize Union Using union across multiple different databases is an interesting optimization method, and union returns data from two unrelated tables, which means that no duplicate rows will occur and the data must be sorted, and we know that sorting is very resource-intensive, especially for large tables. Union ALL can be much faster if you

Java programmer interview questions (86-115) 86. In Struts 2, how does Action obtain the data that the user inputs from the page, and how does it transmit its own data to the view? A: There are three ways for Action to retrieve data from the page: 1) accept parameters through the Action attribute 2) obtain parameters through the domain model 3) ModelDriven ) Action saves data to the Value Stack. View

Android interview questions 1. Which of the following statements about memory reclaim are correct? (B)A. the programmer must create a thread to release the memory.B. The memory reclaim program is responsible for releasing useless memory.C. The memory reclaim program allows programmers to directly release the memory.D. The memory reclaim program can release memory objects at the specified time. 2. The follow

Basic questions about PHP interview questions 1. What methods do you use to solve traffic problems for websites with high traffic volumes? First, check whether the server hardware is sufficient to support the current traffic. second, optimize database access. Third, prohibit external leeching. Fourth, control the download of large files. Fifth, use different host

Spring, hibernate, Struts interview questions from: http://shwenwen.itpub.net/post/34911/486887 How does hibernate work and why?Principle:1. Read and parse the configuration file2. Read and parse the ing information and create sessionfactory3. Open sesssion4. Create transaction Transation5. Persistent operations6. Submit the transaction7. Disable session8. Disable sesstionfactory Why:1. For JDBC access

. Synchronize the data between the main library and the library, and then repeat the action again13. Use a single command to turn off all services except SSHD, Crond, network, Rsyslog services (no power-on automatic)Method One:[[Email protected]~]# for name in ' Chkconfig–list|grep 3:on|awk ' {print '} ' |grep-ev "sshd|crond|rsyslog|network" ';d och Kconfig $name Off;done[Email protected]~]# chkconfig–list|grep 3:onCrond 0:off 1:off 2:on 3:on 4:on 5:on 6:offNetwork 0:off 1:off 2:on 3:on 4:on 5:o

Before I resigned, I gave my company a set of interview questions. What do you think is difficult ?? Oracle Database assessment: 1. Write a jdbc connection to the database and add, delete, modify, and query data code (simply write it ). Answer: PublicstaticvoidMain (String [] args ){ //TODOAuto-generated method stub Connection cn =Null; CallableStatement cstmt =Null; Try{ // Do not do this here, because th

A few questions about SQL and a few questions about SQL When we get a question, we are not eager to answer the question. It will not be worth the candle, but to analyze the ideas, methods, and objectives, we also need to think about whether there are simple methods or general methods to achieve the same effect. In fact

Several PHP interview questions 1. how can I use the php environment variable to get the content of a webpage address? How can I get the IP address? 2. calculate the difference between two dates, for example, 2007-2-5 ~ Date difference of-3-6 3. write a function to implement the following functions:Convert the string "open_door" to "OpenDoor" and "make_by_id" to "MakeById ". 4. write a program to convert th

. In Mixed mode, MySQL distinguishes between the log forms of treated records based on each specific SQL statement executed, that is, choosing between statement and row. The statment in the new version is still the same as before, recording only the statements executed. The new version of MySQL in the row mode is also optimized, not all changes will be in the row mode to record, such as when the table structure changes will be recorded in the statemen

Label:1. Query questions during interviewTable has a, b two columns, using SQL statement, internship, when a column greater than Blie, select a column, otherwise select column B select id1,id2,(case when id1>id2 then id1 else id2 end) as result from t4; Similar to the problem, table T4, Id2 greater than 3 records as qualified, greater than 5 for excellent, otherwise unqualified select Id1,id2, (case when

Web Service Interview Questions and answers What is a Web service? Define people and companies have debated the exact definition of Web Services. at a minimum, however, a Web Service is any piece of software that makes itself available over the Internet and uses a standardized XML messaging system.XML is used to encode all communications to a web service. for example, a client invokes a web service by sen