Programmer Think

ORM framework ORM Object Relational Mapping (Object Relational Mapping) is a technology to solve the mismatch between object-oriented and relational databases. Through the metadata describing the mapping between objects and databases, the objects in the program are automatically persisted to the relational database. Its function is to m ...

In short, it has been almost a year since the real start of project development with Rust, and they are becoming more and more popular with Rust; In this process, I stepped on many pits, and had to make up a lot of abandoned knowledge due to Rust's metamorphosis; Of course, I have a deeper understanding of computers, and my hair naturally becom ...

There are no weak people in life, only those who are unwilling to work hard. 1, What is a transaction Transaction is the basic unit of concurrency control. The so-called transaction is a sequence of operations. These operations are either executed or not executed. It is an inseparable work unit. Transaction is the unit for maintaining ...

Write in front: follow Master Kang of station B to learn the notes summary and self summary of mysql. 1. Create storage function Syntax format: CREATE FUNCTION Function name(Parameter name parameter type,...) RETURNS return type BEGIN Function body #There must be a RETURN statement in the function body END explain: Parameter li ...

JDBC introduction JDBC(Java Database Connectivity) is a common interface (a set of API s) independent of a specific database management system and general SQL database access and operation. It defines the standard Java class libraries used to access the database (java.sql,javax.sql). These class libraries can be used to access database resourc ...

I Several cases of index failure The index does not always take effect. For example, the following situations will lead to index invalidation If there is or in the condition, it will not be used even if some of the conditions are indexed (this is why or is used as little as possible) (user_id is not indexed) Note: to use or and make the index ...

1, MySQL database management 1.1 warehouse and table Database – > data table – > row (record): information used to describe an object Column (field): an attribute used to describe an object 1.2 common data types intintegerfloatSingle precision floating point 4-byte 32-bitdoubleDouble precision floating point 8-byte 64 ...

<property name="password">123456</property> <property name="schemas">ITCAST</property> 123456 ITCAST true ``` After configuration, restart MyCat service; Description of attribute meaning: checkSQLschema When the value is set to true Time, If we execute the statement"select * from test01.user ;" Statement time, MyC ...

After many m1 installation lessons, a truth is summarized Be sure to see what m1 downloaded matches that version, otherwise there will always be various problems in the installation! 1). My linux system version is aarch64 2). Therefore, you must download the corresponding version when downloading mysql, otherwise you will make various e ...

1, JDBC specification 1.1 introduction to JDBC JDBC is the full name of Java Database Connectivity. Its original design intention is to provide a set of unified standards that can be applied to various databases. This set of standards needs to be observed by different database manufacturers, and provide their own implementation schemes for JD ...