Programming VIP

1. Prepare table information 2.MySQL advanced statement 2.1 alias Field alias, table alias Syntax: SELECT "table alias" "Field 1" [AS] "field alias" FROM "table name" [AS] "table alias"; Example: select A.age 'Age' from REGION A order by Age asc; 2.2 sub query: join table Insert ...

1, Basic knowledge 1.1. A data storage procedure   the first step in processing data when storing data. Only by storing the data correctly can we process and analyze it effectively. In mysql, a complete data storage process has four steps: creating a database, confirming fields, creating a data table, and inserting data. From the perspecti ...

0 storage engine introduction myisam storage: if the table does not have high transaction requirements and is mainly query and addition, we consider using myisam storage engine, such as posting table and reply table in bbs Regular defragmentation is required (because the deleted data still exists): optimize table_ name; InnoDB storage: ...

What is a transaction? Database transaction refers to a series of operations performed as a single logical unit of work, either completely or not. To put it simply: a transaction is to bind a pile of SQL statements (usually add, delete and modify operations) together for execution. Either all of them are executed successfully or all of them f ...

Database index failure Database index MySQL optimization (I) MySQL optimization (II) MySQL optimization (III) MySQL optimization (IV) Common cases of index failure or keyword in sql statement;The left column field is not used in the composite index;like starts with%;Type conversion required;There are operations in the index column in w ...

The following picture shows the little sister pointed by the blogger! Hee hee! 1, What is sql injection SQL injection is one of the more common network attacks. It does not use the BUG of the operating system to realize the attack, but for the negligence of programmers when writing, it realizes no account login and even tampers with the ...

Mybatis is a "sql oriented" persistence layer framework. It can dynamically assemble sql, which is extremely flexible. At the same time, it avoids almost all JDBC code, manually setting parameters and obtaining result sets. Its plug-in mechanism allows intercepting calls at a certain point during the execution of mapped statements, an ...

Data table advanced operations Preparation: install MySQL database create database CLASS; use CLASS; create table TEST (id int not null,name char(20) not null,cardid varchar(18) not null unique key,primary key (id)); insert into TEST(id,name,cardid) values (1,'zhangsan','123123'); insert into TEST(id,name,cardid) values (2,'lisi','12 ...

Introduction to TPC and TPC-HAccording to TPC official website( http://tpc.org )TPC is a non-profit company, focusing on developing data centric benchmark standards and disseminating objective and verifiable data to the industry. TPC releases TPC-C, TPC-H and TPC-DS, which are widely used in the industry. TPC-C is the test benchmark for OLTP, w ...

The original content of GreatSQL community cannot be used without authorization. Please contact Xiaobian and indicate the source for reprint.Experimental environmentGreatSQL 8.0.25 InnoDB1. Introduction to index push down1. Index Condition Pushdown is short for ICP.2.MySQL5. Version 6 introduces the function for optimizing queries.3. Under some ...