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The complete code is as follows: public class ExternalActivity extends AppCompatActivity { private EditText infoEdt; private TextView txt; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_external); infoEdt = ...

​ Database benefits 1.Persistent data to local 2.It can realize structured query and facilitate management Database related concepts 1,DB: Database, a container that holds a set of organized data 2,DBMS: Database management system, also known as database software (product), is used for management DB Data in 3,SQL:Structured query langu ...

1. Why master slave copy In a system with complex business, there is a scenario in which an sql statement needs to lock the table, resulting in the temporary inability to use the read service, which will greatly affect the running business. Use master-slave replication, and let the master database be responsible for writing and the slave datab ...

The data system in the group cannot meet the performance requirements when undertaking a business requirement, so some optimizations are made for this scenario, and an article is written here for records. The business scenario is as follows: the caller obtains hundreds of characteristics of a user at a time (characteristics can be understood a ...

sql injection is When the user enters some sql statements that are not the user name or password These statements are not filtered After execution, the injector obtains the information of the database through echo and other methods Water has been used for several days for visual studio 2022 and windows 11, so this article is a little ...

When using Linq to sql in C#, IQueryable and IEnumerable are often confused. This article briefly analyzes the differences and usage scenarios between them. preface Whether Linq to object, Linq to sql or Linq to Entity, IQueryable and IEnumerable are delayed execution. The only difference between them lies in the parameter types of extension ...

Persistence Redis is an in memory database. It needs to be persistent in case of power failure and power loss. RDB is used by default. Generally, we can use it without modifying RDB configuration. RDB (Redis DataBase) What is RDB Redis will create a fork subprocess separately for persistence. In the subprocess, it will cycle all data and wr ...

Python learning log Home page of RBHGO Welcome to pay attention Warm tip: creation is not easy. If reprinted, indicate the source. Thank you for your cooperation~ catalogue Python learning log Lesson 17 - Python database programming DCL (data control language) DCL - > grant or recall user permission - > grant / revoke In ...

Oracle database create user, specify default (create) tablespace, and grant permissions (dba, ETL are required) preface In the actual development process, creating users in the database, specifying tablespaces and assigning permissions to users are the basic operations. The script commands are introduced below. Tip: the following ...

Access Remote Sources with SAP HANA Database Explorer Remote sources are connections to other databases. Virtual tables use remote sources to create local tables that point to data stored in another database. Federated queries use virtual and non virtual tables. To illustrate these concepts, a table will be created in the remote database cont ...