IOS下SQLite的简单使用
資料來源:http://www.cppblog.com/cokecoffe/archive/2012/05/31/176978.html
看着国外网站的教程，写了一个小例子，一个联系人的程序，包括 （姓名、地址、电话）三项内容，通过两个按钮，可以将信息保存或者查询数据库已有的信息。
UI就不说了，比较简单。贴一下关键代码，具体的话还是去看源代码(正想办法传，我这git出点问题)。
/*根据路径创建数据库并创建一个表contact(id nametext addresstext phonetext)*/
UI就不说了，比较简单。贴一下关键代码，具体的话还是去看源代码(正想办法传，我这git出点问题)。
/*根据路径创建数据库并创建一个表contact(id nametext addresstext phonetext)*/
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
NSString *docsDir;
NSArray *dirPaths;
// Get the documents directory
dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
docsDir = [dirPaths objectAtIndex:0];
// Build the path to the database file
databasePath = [[NSString alloc] initWithString: [docsDir stringByAppendingPathComponent: @"contacts.db"]];
NSFileManager *filemgr = [NSFileManager defaultManager];
if ([filemgr fileExistsAtPath:databasePath] == NO)
{
const char *dbpath = [databasePath UTF8String];
if (sqlite3_open(dbpath, &contactDB)==SQLITE_OK)
{
char *errMsg;
const char *sql_stmt = "CREATE TABLE IF NOT EXISTS CONTACTS(ID INTEGER PRIMARY KEY AUTOINCREMENT, NAME TEXT, ADDRESS TEXT,PHONE TEXT)";
if (sqlite3_exec(contactDB, sql_stmt, NULL, NULL, &errMsg)!=SQLITE_OK)
{
status.text = @"创建表失败\n";
}
}
else
{
status.text = @"创建/打开数据库失败";
}
}
}
/*将数据保存只数据库，当按下保存按钮的时候*/
- (IBAction)SaveToDataBase:(id)sender
{
sqlite3_stmt *statement;
const char *dbpath = [databasePath UTF8String];
if (sqlite3_open(dbpath, &contactDB)==SQLITE_OK) {
NSString *insertSQL = [NSString stringWithFormat:@"INSERT INTO CONTACTS (name,address,phone) VALUES(\"%@\",\"%@\",\"%@\")",name.text,address.text,phone.text];
const char *insert_stmt = [insertSQL UTF8String];
sqlite3_prepare_v2(contactDB, insert_stmt, -1, &statement, NULL);
if (sqlite3_step(statement)==SQLITE_DONE) {
status.text = @"已存储到数据库";
name.text = @"";
address.text = @"";
phone.text = @"";
}
else
{
status.text = @"保存失败";
}
sqlite3_finalize(statement);
sqlite3_close(contactDB);
}
}
/*根据输入的姓名来查询数据*/
- (IBAction)SearchFromDataBase:(id)sender
{
const char *dbpath = [databasePath UTF8String];
sqlite3_stmt *statement;
if (sqlite3_open(dbpath, &contactDB) == SQLITE_OK)
{
NSString *querySQL = [NSString stringWithFormat:@"SELECT address,phone from contacts where name=\"%@\"",name.text];
const char *query_stmt = [querySQL UTF8String];
if (sqlite3_prepare_v2(contactDB, query_stmt, -1, &statement, NULL) == SQLITE_OK)
{
if (sqlite3_step(statement) == SQLITE_ROW)
{
NSString *addressField = [[NSString alloc] initWithUTF8String:(const char *)sqlite3_column_text(statement, 0)];
address.text = addressField;
NSString *phoneField = [[NSString alloc] initWithUTF8String:(const char *)sqlite3_column_text(statement, 1 )];
phone.text = phoneField;
status.text = @"已查到结果";
[addressField release];
[phoneField release];
}
else {
status.text = @"未查到结果";
address.text = @"";
phone.text = @"";
}
sqlite3_finalize(statement);
}
sqlite3_close(contactDB);
}
}
