database interview questions and answers pdf

Label:1. Query the sname, Ssex, and class columns of all records in the student table. Select T.sname,t.ssex,t.sclass from student t; 2, the inquiry teacher all units namely does not duplicate depart column. Select * from teacher T where t.depart= ' computer system '; 3. Query all records of student table. Select *from student T; 4. Query all records from 60 to 80 of the scores in the score table. SELECT * FROM Student t where T.sno in (select E.sno from score e where degree between and 80);

: ALTERDATABASEMyDatabaseNameSETOFFLINE; Next, copy the data file to the new location. Use replication instead of moving. You can perform quick rollback in case of any errors. Otherwise, you must perform restoration ). Then, use the following code to notify SQL Server of the new location of each file ALTERDATABASEMyDatabaseName MODIFYFILE (NAME=N'LogicalFileName', FILENAME=N'pathname\filename'); After all files are physically copied and the file location in SQL Server is u

Answers to important questions about PHP and databases Senior man, I clicked Login in login.html directly to usercontroller.php, and do not show anything, my purpose is to verify the successful login to jump directly to mian.html Unsuccessful then jump to error.html, but not successful, ask me what is wrong, there is a question is how to log on after the success of the login to mian.html? Thank you.

Why? Thank you for your answers to important questions related to PHPcode php and databases. Too many? Thank you. PHP code Login.html User System logon PHP code dbconn.class.php PHP code userModel.php prepare($sql);: $result->bind_param("ss",$user_id,$user_password); $user_id=$userid; $user_password=$userpwd;

Answers to important questions about PHP and databases

Interview questions: how to optimize MYSQL database queries and mysql databases. Interview questions: how to optimize MYSQL database queries. mysql database 1. how to optimize the data

Interview questions: Talk about how to optimize MySQL database query, MySQL database 1. Optimize data type There are several types of data in MySQL, and if you are a DBA, you are rigorously checking the data types according to the principles of optimization, but developers may choose what they think is the simplest sc

PB and Database interview questions First part: PB (PB6 ~ PB7) (10 points per topic) 1. Write a global function f_center (), and the parameter Aw_window to the window type so that it is centered automatically. 2. For information on how to access image or text type data in Pb, please give an example. 3. How to detect whether the data window has been modified.

2018/5/31 Oracle Database interview Written questions summaryHttp://www.yjbys.com/qiuzhizhinan/show-308759.html 1/4Oracle Database1. Basic TestingSelect all information for employees in department 30Select * from EMP where deptno=30;The number of the employee who listed the position as (MANAGER), nameSelect empno,ename from emp where job =? Manager?;Find employee

also hope that more users to participate in: http://bbs.database.ccidnet.com/thread.php? FID = 27 Oracle DBA interview questions by B G 1. How many memory layers are in the shared pool? 2. How do you find out from the RMAN catalog if a participant archive log has been backed-up? 3. How can you tell how much space is left on a given file system and how much space each of the file system's subdirectories

(avoid loss of modification) 2) Level two block protocol: increase transaction T on the basis of the first level blocking protocol must read the data R before reading the lock, you can release the read lock after reading (to avoid loss of modification and read dirty data) 3) Level three block protocol: increase the transaction T on the basis of the first level blocking protocol the lock must be read before the data R is read, until the end of the transaction is released (avoid loss of modificat

: This article mainly introduces interview questions: I will talk about how to optimize MYSQL database queries. if you are interested in PHP tutorials, please refer to it. 1. Optimize Data types There are multiple data types in MySQL. if you are a DBA, you are strictly checking the data type according to the optimization principle. However, developers may choose

cannot implement a function other than the ' = ' Logic of the case search function. Case function Matching principle The case function differs from switch in that the case only returns the result of the first match, and Switch will continue the subsequent judgment without interruption, and all matching results will be executed. Case search function is more flexible than simple case function The flexibility of the case search funct

StudentLeft JOIN choice_info choice on choice.student_no = student. ' No 'GROUP byStudent. ' No ') AWHEREA.count > 2;4. Check the names of all students with test scores, name of course and exam results, and place the results in a new permanent table (assuming the new table is named Tb_rel_new)Note: This topic contains new tables and insert query data Inquire SELECTA. ' Name ' Studentname,Course. ' Name ' Coursename,A.gradeFromCourse_info CourseLeft JOIN (SELECTStudent. '

) s#,c#, G respectively represents the student number, the selected course number, and the academic score (1) Use standard SQL nested statements to query the student number and name of the elective course named ' Tax base '? Answer: Select s#, SN from S where s# in (select s# from C,SC where C. c#=sc.c# and cn= ' tax base ') (2) Use standard SQL nested statements to query the student name and affiliation of the elective course number ' C2 '? A: Select Sn,sd from S,SC where s.s#=sc.s# and sc.c#=

) s#,c#, G respectively represents the student number, the selected course number, and the academic score (1) Use standard SQL nested statements to query the student number and name of the elective course named ' Tax base '? Answer: Select s#, SN from S where s# in (select s# from C,SC where C. c#=sc.c# and cn= ' tax base ') (2) Use standard SQL nested statements to query the student name and affiliation of the elective course number ' C2 '? A: Select Sn,sd from S,SC where s.s#=sc.s# and sc.c#=

A few days to a company in Pudong to interview, feel that there is a database query questions did not answer well, self-summary, the next attention.Title: The size of tables in the database, and arranged out. Write the corresponding SQL statement.The code is as follows:CREATE PROCEDURE [dbo].[Gettablespace]@dbNamesysna

rewrite the aof file, the performance impact of this persistence is minimal, but the aof file will continue to grow, aof file over the General Assembly to affect the recovery speed of master restart. Master should not do any persistent work, including memory snapshots and aof log files, in particular, do not enable memory snapshots to persist, if the data is more critical, a slave open aof backup data, the policy is synchronized once per second. Master calls bgrewriteaof rewrite aof file, a

1. The difference between the Union and UNION allis to display the results of multiple slelect statements as a whole.The difference is that union automatically compresses duplicate results in multiple result sets (the system automatically removes the duplicate tuples), and union ALL displays all results (preserving duplicate Ganso), whether or not duplicates.Union is inefficient because it is being scanned for duplicate values. If the merge does not intentionally delete duplicate rows, then use

= { NewSqlParameter ("@number", SqlDbType.NVarChar),NewSqlParameter ("@moneys", SqlDbType.Int),NewSqlParameter ("@name", SqlDbType.NVarChar),}; para[0]. Value = file[0]; para[1]. Value = Convert.ToInt32 (file[1]); para[2]. Value = file[2]; //Database Operations using(SqlConnection conn =NewSqlConnection ("Data Source=.;i Nitial catalog=test; Persist Security info=true; User Id=sa; Password=123