检查数据是否存在之前插入到iPhone的SQLite数据库

Question

我想插入数据到sqlite..hhile插入即时通讯获得重复在我的代码..我看到与它有关的问题和即时通讯了解有关..所有只是帮助我这个代码来检查数据插入到数据库之前存在...

- (IBAction)AddtoFavourites:(id)sender { 
    sqlite3 *database; 
    [email protected]"dataTable.sqlite"; 
    NSArray *documentpath=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
    NSString *documentdir=[documentpath objectAtIndex:0]; 
    dbPath=[documentdir stringByAppendingPathComponent:dbName]; 
    if(sqlite3_open([dbPath UTF8String], &database)==SQLITE_OK){ 
//I want to check data it exists already into database.... 
     NSString *sqlStatement=[NSString stringWithFormat:@"insert into Persons(PersonName,CompanyName,ImgUrl)values(\"%@\",\"%@\",\"%@\")",model.personName,model.companyName,model.imgurl]; 
      const char *insertSQL=[sqlStatement UTF8String]; 
     char *errMsg; 
     sqlite3_exec(database, insertSQL, NULL,NULL,&errMsg); 
     NSLog(@"Add to Favourites");   
    } 
} 

Answer 1

首先使用select查询任何列的为：

const char *sqlStatement = "SELECT PersonName FROM Persons"; 

我猜你会分配到的SQLStatement编制陈述

  while(sqlite3_step(compiledStatement) == SQLITE_ROW) { 
      // Read the data from the result row 
      NSString *aName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 1)]; 


      [dataArray addObject:aName]; 
      NSLog(@"%@",aName); 
} 

将检查这个