PDO basic operation of PHP

The difference between PDO and Mysqli For PHP 5 and above, the following methods are recommended to connect to MySQL: MySQLi extension ("i" means improved) PDO (PHP Data Objects) PDO is used in 12 different databases, MySQL is only for MySQL database. Both support preprocessing statements to ...

Posted by Zssz on Fri, 21 Feb 2020 08:49:47 +0100

springboot ~ integrated DataSource and Druid monitoring configuration

introduce Druid is first a database connection pool. Druid is the best database connection pool at present, surpassing other database connection pools in function, performance and scalability. Druid has deployed more than 600 applications in Alibaba, which has passed the severe test of large-scale deployment of production environment for more t ...

Posted by siric on Wed, 19 Feb 2020 04:40:15 +0100

MySQL query operation

Introduction to MySQL database Learning notes (2) Simple query SELECT column_name1, column_name2 FROM table_name; #select name,phone from person; SELECT * FROM table_name; #select * from person; * indicates all contents in the query table Conditional query where clause is required for condition q ...

Posted by the-hardy-kid on Sun, 16 Feb 2020 05:48:27 +0100

Flash + MySQL + eckarts: realize data visualization

Flask Flask is a lightweight WSGI Web application framework. It is designed to make it easy to get started and has the ability to scale to complex applications. It was originally a simple wrapper around Werkzeug and Jinja and has become one of the most popular Python Web application frameworks. from fl ...

Posted by trinitywave on Thu, 13 Feb 2020 14:37:21 +0100

Dynamic SQL of mybatis

Existence reason When we query in the database, we write fixed SQL, that is to say, we have to write a SQL for each query. But in the program, it is obvious that if there are too many fields in a table, we can query and update according to the combination of any fields. The amount of code is particul ...

Posted by Drabin on Tue, 11 Feb 2020 13:57:06 +0100

(database) 08 multi table query

08 multi table query 1, Multi table query 1. Cartesian set 2, Oracle connection 1. Equivalent connection 2. Multiple join conditions AND and operators 1. Distinguish duplicate column names 2. Alias of table 3. Multi table associated query 4. Non equivalent connection 5. external connection 1. Int ...

Posted by tensitY on Tue, 11 Feb 2020 08:24:15 +0100

The builder mode of GOF23 design mode

Catalog Usage scenarios The essence of builder mode Code example Code call Usage scenarios - we want to build a complex product. For example: Shenzhou spaceship, Iphone. The creation of this complex product. There is a problem that needs to be addressed: • is there a step problem in assembl ...

Posted by FireyIce01 on Mon, 10 Feb 2020 08:30:31 +0100

ElasticSearch index details

Still using mysql for full-text indexing? Try elastic search! Note: the following documents are based on elasticsearch version 7. X, which is different from the old version 1. Format description The data interaction interface of elasticSearch is based on http protocol, and the basic format is as fol ...

Posted by ErcFrtz on Sun, 09 Feb 2020 11:55:43 +0100

Making clear of hive window function

1 Definition Window function, also known as analysis function Analytic functions compute an aggregate value based on a group of rows. They differ from aggregate functions in that they return multiple rows for each group. The group of rows is called a window and is defined by the analytic_clause.Th ...

Posted by xsgatour on Thu, 06 Feb 2020 15:06:54 +0100

ORA-00600 KGLDELETEALLPINSONOBJ1 a BUG crossing 10g/11g/12c

A friend on motianlun encountered a rare ORA-600 error. The first error parameter is KGLDELETEALLPINSONOBJ1. From the naming of KGLDELETEALLPINSONOBJ1, we can quickly guess the basic situation: KGL - Kernel Generic Library cache, which means that the problem lies in the Library Cache level; DELET ...

Posted by Ind007 on Thu, 06 Feb 2020 09:03:03 +0100