Kompex SQLite Wrapper for C++ - Examples

Here you can see some examples.
It shows a part of the functionality of the wrapper and how you can use it.
You can find more examples in the example application (contained in download package).

1. open a database and create a statement instance for sql queries/statements

 
 //opendatabase 
Kompex::sqliteDatabase*pDatabase=newKompex::sqliteDatabase("test.db",sqlITE_OPEN_READWRITE,0); 
//createstatementinstanceforsqlqueries/statements 
Kompex::sqliteStatement*pStmt=newKompex::sqliteStatement(pDatabase); 
 

2. create a new table and fill it with data

 
 //createtableandinsertsomedata 
pStmt->sqlStatement("CREATETABLEuser\ 
(\ 
userIDINTEGERNOTNULLPRIMARYKEY,\ 
lastNameVARCHAR(50)NOTNULL,\ 
firstNameVARCHAR(50),ageINTEGER\ 
)"); 
 
pStmt->sqlStatement("INSERTINTOuser(userID,lastName,firstName,age)\ 
VALUES(1,'Lehmann','Jamie',20)"); 
pStmt->sqlStatement("INSERTINTOuser(userID,age)\ 
VALUES(2,'Burgdorf','Peter',55)"); 
pStmt->sqlStatement("INSERTINTOuser(userID,age)\ 
VALUES(3,'Fernando',18)"); 
pStmt->sqlStatement("INSERTINTOuser(userID,age)\ 
VALUES(4,'Carlene',17)"); 
 

3. use some aggregate functions

 
 pStmt->sqlAggregateFuncResult("SELECTCOUNT(*)FROMuserWHERElastName='Lehmann';"); 
pStmt->sqlAggregateFuncResult("SELECTCOUNT(weight)FROMuser;"); 
pStmt->sqlAggregateFuncResult("SELECTMAX(age)FROMuser;"); 
pStmt->sqlAggregateFuncResult("SELECTMIN(age)FROMuser;"); 
pStmt->sqlAggregateFuncResult("SELECTAVG(age)FROMuser;"); 
pStmt->sqlAggregateFuncResult("SELECTSUM(age)FROMuser;"); 
pStmt->sqlAggregateFuncResult("SELECTTOTAL(age)FROMuser;"); 
 

4. execute and process a sql query

 
 pStmt->sql("SELECT*FROMuserWHEREfirstName='Jamie';"); 
//processallresults 
while(pStmt->FetchRow()) 
{ 
std::cout<<"firstname:"<<pStmt->GetColumnInt(0)<<std::endl; 
std::cout<<"lastname:"<<pStmt->GetColumnString(1)<<std::endl; 
std::cout<<"firstname:"<<pStmt->GetColumnString(2)<<std::endl; 
} 
//donotforgettoclean-up 
pStmt->FreeQuery(); 
 

5. execute a simple transaction

 
 //ifanerroroccurs,arollbackisautomaticallyperformed 
pStmt->BeginTransaction(); 
pStmt->Transaction("INSERTINTOuser(userID,age)VALUES(10,'Makoto',23)"); 
pStmt->Transaction("INSERTINTOuser(userID,age)VALUES(11,'Yura',20)"; 
pStmt->Transaction("INSERTINTOuser(userID,age)VALUES(12,63)"); 
pStmt->CommitTransaction(); 
 

6. here you can see the exception handling

 
 try 
{ 
//tablestructure:userIDINTEGERNOTNULLPRIMARYKEY,lastNameVARCHAR(50) 
pStmt->sqlStatement("INSERTINTOuser(userID,lastName)VALUES(1,'Lehmann')"); 
//thefollowinglinewillthrowanexceptionbecausetheprimarykeyisnotunique 
pStmt->sqlStatement("INSERTINTOuser(userID,'Bergmann')"); 
} 
catch(Kompex::sqliteException&exception) 
{ 
std::cerr<<"ExceptionOccured"<<std::endl; 
exception.Show(); 
} 
 

7. work with a memory database

 
 Kompex::sqliteDatabase*pDatabase=newKompex::sqliteDatabase("scores.db",0); 
//movedatabasetomemory,sothatweareworkonthememorydatabasehence 
pDatabase->MoveDatabaseToMemory(); 
 
Kompex::sqliteStatement*pStmt=newKompex::sqliteStatement(pDatabase); 
//insertsomedatasetsintothememorydatabase 
pStmt->sqlStatement("INSERTINTOscore(id,lastscore,avgscore)VALUES(1,429,341)"); 
pStmt->sqlStatement("INSERTINTOscore(id,avgscore)VALUES(2,37,44)"); 
pStmt->sqlStatement("INSERTINTOscore(id,avgscore)VALUES(3,310,280)"); 
 
//savethememorydatabasetoafile 
//ifyoudon'tdoit,alldatabasechangeswillbelostafterclosingthememorydatabase 
pDatabase->SaveDatabaseFromMemoryToFile("newscores.db"); 
 

8. get some result values via column name (more flexible and a little bit slower than the common way)

 
 pStmt->sql("SELECT*FROMuserWHERElastName='Lehmann';"); 
 
//processallresults 
while(pStmt->FetchRow()) 
{ 
std::cout<<"firstName:"<<pStmt->GetColumnString("firstName")<<std::endl; 
std::cout<<"age:"<<pStmt->GetColumnInt("age")<<std::endl; 
} 
 
//donotforgettoclean-up 
pStmt->FreeQuery(); 
 

9. two possibilities to update data in the database

 
 //thefirstway 
pStmt->sqlStatement("UPDATEuserSETweight=51.5,age=18WHEREfirstName='Carlene'"); 
 
//thesecondway-withapreparedstatement 
pStmt->sql("UPDATEuserSETlastName=@lastName,age=@ageWHEREuserID=@userID"); 
 
//bindanintegertothepreparedstatement 
pStmt->BindString(1,"Urushihara");//bindlastName 
pStmt->BindInt(2,56);//bindage 
pStmt->BindInt(3,2);//binduserID 
 
//executeitandclean-up 
pStmt->ExecuteAndFree(); 
 

原文链接：https://www.f2er.com/sqlite/201844.html

Kompex SQLite Wrapper for C++ - Examples

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