iOS SQLite Database

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Introduction

Using SQLite to handle data in iOS. If you already understand SQL, you can easily master SQLite database operations.

Steps for the Example

1. Create a simple View-based application.
2. Select the project file, then select the target, and add the libsqlite3.dylib library to the Linked Frameworks and Libraries.
3. Create a new file by selecting File → New → File…, then choose Objective-C class, and click Next.
4. Set Subclass of to NSObject, and name the class DBManager.
5. Click Create.
6. Update DBManager.h, as shown below:

#import <Foundation/Foundation.h>
#import <sqlite3.h>

@interface DBManager : NSObject
{
    NSString *databasePath;
}

+ (DBManager*)getSharedInstance;
- (BOOL)createDB;
- (BOOL) saveData:(NSString*)registerNumber name:(NSString*)name department:(NSString*)department year:(NSString*)year;
- (NSArray*) findByRegisterNumber:(NSString*)registerNumber;

@end

7. Update DBManager.m, as shown below:

#import "DBManager.h"

static DBManager *sharedInstance = nil;
static sqlite3 *database = nil;
static sqlite3_stmt *statement = nil;

@implementation DBManager

+ (DBManager*)getSharedInstance
{
    if (!sharedInstance)
    {
        sharedInstance = [[super allocWithZone:NULL]init];
        ;
    }
    return sharedInstance;
}

- (BOOL)createDB
{
    NSString *docsDir;
    NSArray *dirPaths;
    // Get the documents directory
    dirPaths = NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES);
    docsDir = dirPaths;

    // Build the path to the database file
    databasePath = [ initWithString: [docsDir stringByAppendingPathComponent: @"student.db"]];

    BOOL isSuccess = YES;
    NSFileManager *filemgr = ;

    if ([filemgr fileExistsAtPath: databasePath ] == NO)
    {
        const char *dbpath = ;

        if (sqlite3_open(dbpath, &database) == SQLITE_OK)
        {
            char *errMsg;
            const char *sql_stmt = "create table if not exists studentsDetail (regno integer primary key, name text, department text, year text)";
            if (sqlite3_exec(database, sql_stmt, NULL, NULL, &errMsg) != SQLITE_OK)
            {
                isSuccess = NO;
                NSLog(@"Failed to create table");
            }
            sqlite3_close(database);
            return isSuccess;
        }
        else
        {
            isSuccess = NO;
            NSLog(@"Failed to open/create database");
        }
    }
    return isSuccess;
}

- (BOOL) saveData:(NSString*)registerNumber name:(NSString*)name department:(NSString*)department year:(NSString*)year;
{
    const char *dbpath = ;

    if (sqlite3_open(dbpath, &database) == SQLITE_OK)
    {
        NSString *insertSQL = [NSString stringWithFormat:@"insert into studentsDetail (regno,name, department, year) values ("%d","%@", "%@", "%@")",, name, department, year];
        const char *insert_stmt = ;
        sqlite3_prepare_v2(database, insert_stmt,-1, &statement, NULL);

        if (sqlite3_step(statement) == SQLITE_DONE)
        {
            return YES;
        }
        else
        {
            return NO;
        }
        sqlite3_reset(statement);
    }
    return NO;
}

- (NSArray*) findByRegisterNumber:(NSString*)registerNumber
{
    const char *dbpath = ;

    if (sqlite3_open(dbpath, &database) == SQLITE_OK)
    {
        NSString *querySQL = [NSString stringWithFormat: @"select name, department, year from studentsDetail where regno="%@"",registerNumber];
        const char *query_stmt = ;
        NSMutableArray *resultArray = [init];

        if (sqlite3_prepare_v2(database, query_stmt, -1, &statement, NULL) == SQLITE_OK)
        {
            if (sqlite3_step(statement) == SQLITE_ROW)
            {
                NSString *name = [ initWithUTF8String: (const char *) sqlite3_column_text(statement, 0)];
                [resultArray addObject:name];

                NSString *department = [ initWithUTF8String: (const char *) sqlite3_column_text(statement, 1)];
                [resultArray addObject:department];

                NSString *year = [initWithUTF8String: (const char *) sqlite3_column_text(statement, 2)];
                [resultArray addObject:year];

                return resultArray;
            }
            else
            {
                NSLog(@"Not found");
                return nil;
            }
            sqlite3_reset(statement);
        }
    }
    return nil;
}

8. Update ViewController.xib as shown in the figure below:

9. Create IBOutlets for the text fields shown above.
10. Create IBActions for the buttons shown above.
11. Update ViewController.h, as shown below:

#import <UIKit/UIKit.h>
#import "DBManager.h"

@interface ViewController : UIViewController<UITextFieldDelegate>
{
    IBOutlet UITextField *regNoTextField;
    IBOutlet UITextField *nameTextField;
    IBOutlet UITextField *departmentTextField;
    IBOutlet UITextField *yearTextField;
    IBOutlet UITextField *findByRegisterNumberTextField;
    IBOutlet UIScrollView *myScrollView;
}

- (IBAction)saveData:(id)sender;
- (IBAction)findData:(id)sender;

@end

12. Update ViewController.m, as shown below:

#import "ViewController.h"

@interface ViewController ()
@end

@implementation ViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *) nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self)
    {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    ;
    // Do any additional setup after loading the view from its nib.
}

- (void)didReceiveMemoryWarning
{
    ;
    // Dispose of any resources that can be recreated.
}

- (IBAction)saveData:(id)sender
{
    BOOL success = NO;
    NSString *alertString = @"Data Insertion failed";

    if (regNoTextField.text.length>0 &&
        nameTextField.text.length>0 &&
        departmentTextField.text.length>0 &&
        yearTextField.text.length>0 )
    {
        success = [saveData: regNoTextField.text
                                                    name:nameTextField.text
                                                department: departmentTextField.text
                                                      year:yearTextField.text];
    }
    else
    {
        alertString = @"Enter all fields";
    }

    if (success == NO)
    {
        UIAlertView *alert = [initWithTitle: alertString
                                                       message:nil
                                                         delegate:nil
                                                cancelButtonTitle:@"OK"
                                                otherButtonTitles:nil];
        ;
    }
}

- (IBAction)findData:(id)sender
{
    NSArray *data = [findByRegisterNumber: findByRegisterNumberTextField.text];

    if (data == nil)
    {
        UIAlertView *alert = [initWithTitle: @"Data not found"
                                                       message:nil
                                                         delegate:nil
                                                cancelButtonTitle: @"OK"
                                                otherButtonTitles:nil];
        ;

        regNoTextField.text = @"";
        nameTextField.text = @"";
        departmentTextField.text = @"";
        yearTextField.text = @"";
    }
    else
    {
        reg