Unity connects to the database

1. First, in the Assets So let's create one Plugins Folder
2. stay Plugins Put... Under the folder Mysql.Data.dll,System.Data.dll,System.Drawing.dll below
3. newly build C# Code file
open C# file , introduce using Mysql.Data.MysqlClient
Create connection objects
string s=“server=localhost;database=student;userid=root;password=root;”
MysqlConnection con=new MysqlConnection(s);
con.open();
string sql=“insert into xinxi value(“ Rage ”,888)”;
MysqlCommand msc=new MysqlCommand(sql,con);
if(msc.ExecuteNorQuery()>0){

print(“ Successful operation ”);
}
else{
print(“ operation failed ”);
}
MysqlDataReader reader=msc.ExecutReader();
while(reader.Read()){
int id=reader.GetInt(“id”);
string name=reader.GetString(“name”);
print(id+"\t"+name);
}
reader.close();
con.close();
2.count(*) Return the number of all records in the table , It is equivalent to counting all rows
count(1) Return the number of rows that are not empty
count( Name ) Returns the number of rows in the specified column , Does not contain empty records
3. Multi-table query
Internal connection ：select surface . Field , surface . Field from Table name inner join Table name on Foreign keys = Primary key
Left connection ：select Table name . Field , Table name . Field from Table name inner join Table name on Foreign keys = Primary key
4. Aggregate functions
count() How many lines
max() For maximum
min() For the minimum
avg() averaging
sum() Sum up
group by grouping
order by desc Descending