• ORM


    Object relational mapping (ORM) Its function is to make a mapping between relational database and object, so that we don’t need to deal with complex SQL statements when we operate the database. Net environment ORM: 1. Sqlsugar: is a lightweight MSSQL ORM with similar and easy-to-use syntax as EF in addition to the performance comparable […]

  • 1.4 master the use of logging tools — Notes on the first line of Android code (version 2)


    The logging tool class in Android is log (Android. Util. Log), which provides the following five methods for us to print logs. Log. V(): used to print the most trivial and meaningful log information. The corresponding level of verbose is the lowest in Android logs. Log. D(): used to print some debugging information, which should […]

  • Oracle added, deleted, modified and queried by mybatis


    Oracle added, deleted, modified and queried by mybatis I. query Common query (return common persistent layer objects. Because the style of database fields is different from Java, establish a map map) <resultMap type=”com.xxx.domain.RuleCondition” id=”RuleConditionResultMapWithoutBondList”> <id column=”RC_ID” jdbcType=”NUMERIC” property=”ruleConditionId”/> <result column=”RULE_CAT1″ jdbcType=”VARCHAR” property=”ruleCatOne”/> <result column=”RULE_CAT2″ jdbcType=”VARCHAR” property=”ruleCatTwo”/> <result column=”RC_OPER_TYPE” jdbcType=”VARCHAR” property=”ruleOperateSymbol”/> <result column=”RULE_REF” jdbcType=”VARCHAR” property=”ruleRef”/> <result […]

  • Learning notes of design pattern: (19) strategic pattern


    This note is excerpted from: https://www.cnblogs.com/patrick liu/p/8057654.html. Record the learning process for future reference.     I. Introduction Today we are going to talk about the seventh pattern of behavioral design pattern — strategic pattern. In real life, examples of strategic patterns are also very common. For example, in a company, there will be a variety […]

  • Classic examples of database and information system


    Classic examples of database and information system @Langyuan qihan Updated on: January 3, 2020 This is the final version. The classic examples are from the course “database and information system”. They are only for academic exchange and final review. If there is any mistake, please point out the source when reprinting! 1、 Basic concept verification […]

  • Efficient development, a super practical idea development plug-in


    Today, I want to share a very common and practical idea plug-inFree Mybatis plugin。 We usually write a large number of SQL statements in our development. In general, we can write simple statements in the way of annotation (@ select, @ update, @ delete), but some are complex, such as single table multi condition query, […]

  • Get the description value of the column in the data table


    Before that, I wrote the description of MS SQL adding fields https://www.cnblogs.com/insus/p/12106589.html Now, we get the description values of these fields. Let’s start with a select statement:   SELECT * FROM sys.extended_properties GO Source Code   In the above SQL statement, although we get the described value, we don’t know which table and which field […]

  • Three ways to batch update mybatis


    Mybatis implements batch update operationMethod 1: <update id=”updateBatch” parameterType=”java.util.List”> <foreach collection=”list” item=”item” index=”index” open=”” close=”” separator=”;”> update tableName <set> name=${item.name}, name2=${item.name2} </set> where id = ${item.id} </foreach> </update> However, by default, the SQL statement in the mybatis mapping file does not support the execution of multiple SQL statements ending with ‘;’. So you need to […]

  • View MySQL execution plan


    1. MySQL syntax MySQL provides the explain syntax for query analysis. Add an “explain” before the SQL statement. By default, MySQL profiling is turned off, so you must first turn on profiling set profiling=”ON” mysql> show variables like “%profi%”; +————————+——-+ | Variable_name | Value | +————————+——-+ | profiling | ON | Show processlist; view the […]

  • Example of seq2seq model used by Python for NLP: neural machine translation with keras


    Original link:http://tecdat.cn/?p=8438 In this paper, we will see how to create a language translation model, which is also a very famous application of neural machine translation. We will use the seq2seq architecture to create our language translation model through Python’s keras library. It is assumed that you have a good understanding of cyclic neural networks, […]

  • C language note 05 “judgment & cycle & function”


    judge C languageNonzeroandNot emptyThe value of is assumed to betrue, putZeroornullPresumed to befalse。 Here is the general form of a typical judgment structure in most programming languages: Judgement sentence C language provides the following types of judgment statements. Click on the link to see the details of each type. Sentence describe If statement OneIf statementConsists […]

  • Tidb source reading series (XVI) insert statement details


    In the previous article “tidb source reading series (IV) insert statement Overview”, we have introduced the general process of insert statement. Why do I need to write a separate article for insert? Because in tidb, simply inserting a piece of data is the simplest and most commonly used case; what’s more complicated is to set […]