iOS - SQLite Database 操作数据库
2024-10-11 08:58:58
iOS - SQLite Database 操作数据库
Sqlite 能被用在ios上做数据处理用,只要你懂得一点sql 就很容易使用sqlite
1:创建一个简单的View based application2:现在你的项目文件,选择targets 并从库中选择libsqlite3.dylib添加到框架中
3:我们创建一个新的文件 File->New->File->选择Objective C class 并点击next
4:类名称取名为DBManager 子类为NSObject
5:选择创建
6:更新DBManager.h文件
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#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:更新DBManager.m文件
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#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]; [sharedInstance createDB]; } return sharedInstance; } -( BOOL )createDB{ NSString *docsDir; NSArray *dirPaths; // Get the documents directory dirPaths = NSSearchPathForDirectoriesInDomains ( NSDocumentDirectory , NSUserDomainMask , YES ); docsDir = dirPaths[0]; // Build the path to the database file databasePath = [[ NSString alloc] initWithString: [docsDir stringByAppendingPathComponent: @ "student.db" ]]; BOOL isSuccess = YES ; NSFileManager *filemgr = [ NSFileManager defaultManager]; if ([filemgr fileExistsAtPath: databasePath ] == NO ) { const char *dbpath = [databasePath UTF8String]; 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 = [databasePath UTF8String]; if (sqlite3_open(dbpath, &database) == SQLITE_OK) { NSString *insertSQL = [ NSString stringWithFormat:@"insert into studentsDetail (regno,name, department, year) values (\ "%d\",\"%@\", \"%@\", \"%@\")" ,[registerNumber integerValue], name, department, year]; const char *insert_stmt = [insertSQL UTF8String]; 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 = [databasePath UTF8String]; if (sqlite3_open(dbpath, &database) == SQLITE_OK) { NSString *querySQL = [ NSString stringWithFormat: @"select name, department, year from studentsDetail where regno=\ "%@\"" ,registerNumber]; const char *query_stmt = [querySQL UTF8String]; NSMutableArray *resultArray = [[ NSMutableArray alloc]init]; if (sqlite3_prepare_v2(database, query_stmt, -1, &statement, NULL ) == SQLITE_OK) { if (sqlite3_step(statement) == SQLITE_ROW) { NSString *name = [[ NSString alloc] initWithUTF8String: ( const char *) sqlite3_column_text(statement, 0)]; [resultArray addObject:name]; NSString *department = [[ NSString alloc] initWithUTF8String: ( const char *) sqlite3_column_text(statement, 1)]; [resultArray addObject:department]; NSString *year = [[ NSString alloc]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:更新ViewController.xib如图
9:为上面的text fields创建一个IBOutlets
10:为上面按钮创建一个 IBAction
11:更新 ViewController.h文件
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#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:更新ViewController.m文件
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#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 { [ super viewDidLoad]; // Do any additional setup after loading the view from its nib. } - ( void )didReceiveMemoryWarning { [ super 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 = [[DBManager getSharedInstance]saveData: regNoTextField.text name:nameTextField.text department: departmentTextField.text year:yearTextField.text]; } else { alertString = @ "Enter all fields" ; } if (success == NO ) { UIAlertView *alert = [[UIAlertView alloc]initWithTitle: alertString message: nil delegate: nil cancelButtonTitle:@ "OK" otherButtonTitles: nil ]; [alert show]; } } -( IBAction )findData:( id )sender{ NSArray *data = [[DBManager getSharedInstance]findByRegisterNumber: findByRegisterNumberTextField.text]; if (data == nil ) { UIAlertView *alert = [[UIAlertView alloc]initWithTitle: @ "Data not found" message: nil delegate: nil cancelButtonTitle: @ "OK" otherButtonTitles: nil ]; [alert show]; regNoTextField.text = @ "" ; nameTextField.text =@ "" ; departmentTextField.text = @ "" ; yearTextField.text =@ "" ; } else { regNoTextField.text = findByRegisterNumberTextField.text; nameTextField.text =[data objectAtIndex:0]; departmentTextField.text = [data objectAtIndex:1]; yearTextField.text =[data objectAtIndex:2]; } } #pragma mark - Text field delegate -( void )textFieldDidBeginEditing:(UITextField *)textField{ [myScrollView setFrame:CGRectMake(10, 50, 300, 200)]; [myScrollView setContentSize:CGSizeMake(300, 350)]; } -( void )textFieldDidEndEditing:(UITextField *)textField{ [myScrollView setFrame:CGRectMake(10, 50, 300, 350)]; } -( BOOL ) textFieldShouldReturn:(UITextField *)textField{ [textField resignFirstResponder]; return YES ; } @end |
最后输出运行结果为:
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