Category: Database

Program life – software professionals need to have six basic qualities

Basic quality is good coding, coding capacity directly determines the efficiency of project development. This requires software engineers proficient in at least one programming language, such as the current domestic enterprises commonly used C / C + +, VB and the world’s most popular Java language, familiar with its basic grammar, technical features and API (Application […]

Database connection query types and applications

  In database development, achieve performance through single table, and sometimes need to combine a query to find the set of records that we need, this time we will use the connection to query. The join queries include the following aspects: Within the connection Within the connection is generally the most commonly used, also known […]

MYSQL three insert contrast: a single insertion the Load DATA, storage process

Such as reprint, please indicate: Today, MYSQL for bulk data insert a test focusing on learning. Ordinary each insert, the LOAD DATA instructions, call a stored procedure in three ways contrast The use of the time, to tell you inserted in different ways, the efficiency is greatly different.Now based on 100,000 data, for example. Database SQL […]

Learning technology trilogy: WHAT, HOW, WHY

In recent days, some friends in the mail inside asked me about learning problems. Many people think that working for a few years, but also learn a lot of libraries, and frameworks, and even the language, but the feeling is not much to improve their ability to. So today is my personal experience in this regard. I […]

How to make your SQL run faster

—- Using SQL tend to fall into the trap that is too focused on the results are correct, while ignoring the performance differences that may exist between different implementations, this difference in performance in large or complex OLTP (online transaction processing or decision support system DSS) database environment has been particularly evident. I found work in […]

Close the dialog box, heard a “boom” is heard

Last night to do the project, add a button event code, test, close the dialog box “boom” error sound, without any error dialog box pops up, but the process has not been closed. This should be when debugging assertion is activated, appears the error sound. Look at the results, no signs of error. Last debugging […]

Solve There is no READABLE property named ‘SID’

Solve There is no READABLE property named ‘SID’ <insert id=”insertStudent” parameterClass=”Student”> INSERT INTO STUDENT (SID, SNAME, MAJOR, BIRTH, SCORE) VALUES (# sid #, # sname #, # major #, # birth #, # score #) </ Insert> Capital above the table in the database field name The following lowercase sid is the name of the […]

About group by and having (database)

Introduced GROUP BY and HAVING clauses, first talk about a special function in the SQL language: aggregate functions such as SUM, COUNT, MAX, AVG, etc.. These functions and other functions of the fundamental difference is that they are generally many records. SELECT SUM (population) FROM BBC Here SUM function in all returns records on the population […]

The 10gR2 in AWR, ash, addm, Statspack report of difference

10gR2 AWR report is actually extension of statpack report the course 10gR2 or retained statpack, and statpack also increased monitoring of stream_pool, awr statpack difference awr snapshot of the collection and maintenance of more automated, the default reserved a snapshot of the seven-day and can be dbms_workload_repository table to modify the snapshot collection frequency and […]