在我的应用程序中，我使用 SQLite 数据库来存储数据。这是用于插入数据的示例代码
在我的主课中，我如下调用这些方法
-(IBAction)insertButtonAction:(id)sender
{
BOOL isRollNum;
Database *db = [[Database alloc]init];
if ([rollNumberTxtFld.text length]>0)
{
isRollNum = [db checkForRollNumber:rollNumberTxtFld.text];
if (isRollNum == YES)
{
UIAlertView *errorAlert = [[UIAlertView alloc] initWithTitle:@"Error" message:@"Student with specified roll number already available" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil, nil];
[errorAlert show];
}
else
{
if ([nameTxtFld.text length]>0 && [rollNumberTxtFld.text length]>0 )
{
NSString *name = nameTxtFld.text;
NSString *num = rollNumberTxtFld.text;
int age = [ageTxtFld.text intValue];
NSString *address1 = address1TxtFld.text;
NSString *address2 = address2TxtFld.text;
NSString *mobile = mobileTxtFld.text;
NSString *class =classTxtFld.text;
NSLog(@"%@ %@ %d %@ %@ %@ %@ ",name,num,age,address1,address2,mobile,class);
NSString* insert_stmt = NULL;
insert_stmt = [NSString stringWithFormat:@"insert into friends(name,rollnumber,age,address1,address2,mobile,class) values('%@', '%@', '%d', '%@', '%@', '%@', '%@')",name,num,age,address1,address2,mobile,class,nil ];
Database *db = [[Database alloc]init];
BOOL inserted = [db insertIntoDB:insert_stmt];
if (inserted == YES)
{
insertReenterAlert = [[UIAlertView alloc] initWithTitle:@"Success" message:@"Inserted" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil, nil];
[insertReenterAlert show];
}
else
{
insertReenterAlert = [[UIAlertView alloc] initWithTitle:@"Failed" message:@"Not Inserted" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil, nil];
[insertReenterAlert show];
}
}
else
{
insertReenterAlert = [[UIAlertView alloc] initWithTitle:@"Error" message:@" Please enter required fields and try again." delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil, nil];
[insertReenterAlert show];
}
}
}
else
{
insertReenterAlert = [[UIAlertView alloc] initWithTitle:@"Error" message:@" Please enter required fields and try again." delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil, nil];
[insertReenterAlert show];
}
}
此方法用于检查我们要插入的卷号是否已经存在于数据库表中。
-(BOOL)checkForRollNumber:(NSString *) num
{
rollNumberArray = [[NSMutableArray alloc] init];
NSFileManager *fileManager = [NSFileManager defaultManager];
dbPath = [[NSBundle mainBundle]pathForResource:@"FriendsList"ofType:@"sqlite"];
NSLog(@"dbPath %@",dbPath);
BOOL success = [fileManager fileExistsAtPath:dbPath];
int rowCount = 0;
if (success)
{
if (sqlite3_open([dbPath UTF8String], &database) == SQLITE_OK)
{
const char* sqlStatement = "SELECT COUNT(rollnumber) FROM friends ";
sqlite3_stmt* statement;
if( sqlite3_prepare_v2(database, sqlStatement, -1, &statement, NULL) == SQLITE_OK )
{
if( sqlite3_step(statement) == SQLITE_ROW )
rowCount = sqlite3_column_int(statement, 0);
}
else
{
NSLog( @"Failed from sqlite3_prepare_v2. Error is: %s", sqlite3_errmsg(database) );
}
sqlite3_finalize(statement);
sqlite3_close(database);
}
}
NSLog(@"rowCount %d",rowCount);
if (success)
{
if(sqlite3_open([dbPath UTF8String], &database) == SQLITE_OK)
{
const char *selectSQL = "SELECT rollnumber FROM friends";
sqlite3_stmt *statement;
if (sqlite3_prepare_v2(database, selectSQL, -1, &statement, NULL) == SQLITE_OK)
{
while (sqlite3_step(statement) == SQLITE_ROW)
{
for ( int i=0; i<rowCount; i++ )
{
NSLog(@"i %d",i);
NSString *str = [NSString stringWithUTF8String:(char *) sqlite3_column_text(statement, 0)];
[rollNumberArray addObject:str];
NSLog(@"rollNumberArray: %@",[rollNumberArray objectAtIndex:i]);
}
}
for ( int i=0; i<[rollNumberArray count]; i++ )
{
NSLog(@"[rollNumberArray objectAtIndex:%d] %@ == num %@",i,[rollNumberArray objectAtIndex:i],num);
if ([[rollNumberArray objectAtIndex:i] intValue] == [num intValue])
{
NSLog(@"FOUND");
return YES;
}
else
{
NSLog(@"NOT FOUND");
return NO;
}
}
}
else
{
NSLog(@"Statement Not Prepared");
return NO;
}
sqlite3_finalize(statement);
}
else
{
NSLog(@"Database Not Opened");
return NO;
}
sqlite3_close(database);
}
else
{
NSLog(@"File Not Opened");
return NO;
}
}
这是向表中插入数据的方法
-(BOOL) insertIntoDB :(NSString *) insert_stmt
{
NSFileManager *fileManager = [NSFileManager defaultManager];
dbPath = [[NSBundle mainBundle]pathForResource:@"FriendsList"ofType:@"sqlite"];
NSLog(@"dbPath %@",dbPath);
BOOL success = [fileManager fileExistsAtPath:dbPath];
if (success)
{
if(sqlite3_open([dbPath UTF8String], &database) == SQLITE_OK)
{
const char *insertSQL = [insert_stmt UTF8String];
sqlite3_stmt *statement;
if (sqlite3_prepare_v2(database, insertSQL, -1, &statement, NULL) == SQLITE_OK) //**Always not entering into this if**
{
if (sqlite3_step(statement) == SQLITE_DONE)
{
NSLog(@"Succesfully added in DB");
return YES;
}
else
{
NSLog(@"Not added in DB");
return NO;
}
}
else
{
NSLog(@"Statement Not Prepared");
return NO;
}
sqlite3_finalize(statement);
}
else
{
NSLog(@"Database Not Opened");
return NO;
}
sqlite3_close(database);
}
else
{
NSLog(@"File Not Opened");
return NO;
}
}
它不满足这个条件sqlite3_prepare_v2(database, selectSQL, -1, &statement, NULL) == SQLITE_OK) 并且只有第一次添加值。任何人都可以帮助或建议我。
提前致谢。