Archive for the ‘Database knowledge’ Category
How to fix Oracle 10g can not be Installed in the Windows 7 Ultimate 64 bit
Sometimes we will meet this problem.When we install the oralce 10g in windows 7,the installation can not enter the graphical interface .No matter how to run the installation file is unable to enter the graphical interface.Change the compatibility setting also does not work.Even re-install windows 7 32 bit.Such a simple question difficult to me.The oracle installation log message is as follows: Read more
Sometime we will meet the problem of can not connect to MySQL server on 'localhost' (10061),how to solve this problem?
The possible reasons for this problem.
1, MySQL service does not start, generally due to in exceptional circumstances MySQL can not start , for example, no available disk space, my.ini basedir path settings error in the MySQL, etc.
2, MySQL server resource constraints, leading to not connect.
The solutions: Read more
My linux version is centos5.5, kernel version is 2.6.18-194.el5.Install Oracle 11g in linux system preferably 1G memory, 2G of swap space,and at least 4.5G space on hard disk.Follow the steps to install the Oracle 11g .
Download the corresponding version of the Oracle on Oracle official website.I have downloaded Oracle for linux X86.
2.Create the Oracle user in Linux, and the management group .
Login Linux as root user,and execute the following command: Read more
MS SQL server is a computer application that offers advanced relational database management services to the enterprises. Few of the essential points that make it part of an advantageous Enterprise Resource Planning (ERP) proposition can be given as:
Offers complete data solution from data mining to data analysis
MS SQL server produced by Microsoft has brought limitless possibilities to the enterprising solutions available for today's business. This enterprise level database management server from Microsoft has undergone many changes over the years to evolve in its present form. Normally a small or micro enterprise has to face challenges in the areas of execution, lack of lucidity in organizational and professional maneuver. Because of unanalyzed data or unevaluated records, a company finds it difficult to gauge the pace of work. Similarly it is also difficult to record the progress of a team working on a project and the status details of the supervisor or administrator monitoring the entire project. In today's world the volume of data is piling up in leaps and bounds and managing them efficiently is becoming quite a challenge for the companies. A company has to search through voluminous data while looking for certain information. This task which is also known as data-mining is a tedious and time-consuming task. MS SQL server helps in great deal in the data mining for records. SQL server caters to the needs of multi-users. It allocates available resources among the users without compromising on the hardware efficiency. Read more
Difference Between Mysql and Oracle
When we use the database of Mysql and Oracle we will find there are many differences between them.Now let us have a look at these differences.
1. Oracle is a large database and Mysql is a small and medium databases, Oracle's market share is 40%, Mysql only about 20%, at the same time the Mysql is open source but Oracle price is very high.
2. Oracle support large concurrent and large views, is the best OLTP tools.
Oracle Date Functions Usage and Examples
All the Oracle date functions list is the following:
Oracle date function 1.Add_Months
The syntax for the add_months function is:
Add_Months(date,months) Get a date added or minused the months.
select add_months(date,1) from dual
select add_months(date,-1) from dual
Oracle date function 2.Current_date
the Solution of MMC can not open the SQL Server Enterprise Manager.MSC
MMC can not open the file C:\Program Files\Microsoft SQL Server\80\Tools\BINN\SQL Server Enterprise Manager.MSC.
This may be because the file does not exist, is not an MMC console, or a later version of MMC to create. May also be because you do not have sufficient permissions to access this file.
To see on your hard drive the file, if it gets to another partition, see if you can open: Read more
error solution of MYSQL Based the ERROR 1130: Host is not allowed to connect to this MySQL server
MySQL ERROR 1130: Host 'XXXXXX' is not allowed to connect to this MySQL server.
The two solutions of this problem:
Execute the command:
Today to introduce six useful MySQL's SQL statements, many people may have to implement these functions with PHP.
1 calculate the number of years
You want to calculate the birthday person how old.
SELECT DATE_FORMAT (FROM_DAYS (TO_DAYS (now ()) - TO_DAYS (@ dateofbirth)), '% Y') + 0;
2 the difference between the two time
Made the difference between two datetime values. Assuming datetime dt1 and dt2 are the type of the format 'yyyy-mm-dd hh: mm: ss', then the number of seconds difference between them is:
UNIX_TIMESP (dt2) - UNIX_TIMESP (dt1)
Divided by 60 is the difference between the number of minutes divided by 3600 is the difference between the number of hours, then divided by 24 is the difference between the number of days.
3 shows a column appeared in the value of N times
GROUP BY id
HAVING COUNT (*) = N;
4 calculation of working days between two dates Read more