ios对SQLite3的使用

ios对SQLite3的使用

一、在Firefox中打开sqlite3（如果没有，选择工具->附加组件，添加即可）新建sqlite3数据库,Contacts,

建立一个members表，字段 id,integer,主键，自增;name,varchar;email,varchar,null;birthday,datetime,null。

向表中添加一些数据：

二、新建Empty Appliation，添加一个HomeViewController，和一个组件libsqlite3.dylib,来支持对sqlite3的连接，关闭，增删改查等操作。

1. HomeViewController.h代码：

#import <UIKit/UIKit.h>

#import "sqlite3.h"

@interface HomeViewController : UIViewController{

sqlite3 *db; //声明一个sqlite3数据库

}

- (NSString *)filePath;//数据库文件的路径。一般在沙箱的Documents里边操作

@end

2. HomeViewController.m代码：

#import "HomeViewController.h"

@interface HomeViewController ()

@end

@implementation HomeViewController

//该方法用于返回数据库在Documents文件夹中的全路径信息

- (NSString *)filePath{

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

NSString *documentsDir = [paths objectAtIndex:0];

return [documentsDir stringByAppendingPathComponent:@"Contacts.sqlite"];

}

//打开数据库的方法

- (void)openDB{

if (sqlite3_open([[self filePath] UTF8String], &db) != SQLITE_OK) {

sqlite3_close(db);

NSAssert(0, @"数据库打开失败。");

}

}

//插入数据方法

- (void)insertRecordIntoTableName:(NSString *)tableName

withField1:(NSString *)field1 field1Value:(NSString *)field1Value

andField2:(NSString *)field2 field2Value:(NSString *)field2Value

andField3:(NSString *)field3 field3Value:(NSString *)field3Value{

/*方法1：经典方法

NSString *sql = [NSString stringWithFormat:@"INSERT INTO ‘%@‘ (‘%@‘, ‘%@‘, ‘%@‘) VALUES(‘%@‘, ‘%@‘, ‘%@‘)", tableName, field1, field2, field3, field1Value, field2Value, field3Value];

char *err;

if (sqlite3_exec(db, [sql UTF8String], NULL, NULL, &err) != SQLITE_OK) {

sqlite3_close(db);

NSAssert(0, @"插入数据错误！");

}

*/

//方法2：变量的绑定方法

NSString *sql = [NSString stringWithFormat:@"INSERT INTO ‘%@‘ (‘%@‘, ‘%@‘, ‘%@‘) VALUES (?, ?, ?)",tableName, field1, field2, field3];

sqlite3_stmt *statement;

if (sqlite3_prepare_v2(db, [sql UTF8String], -1, &statement, nil) == SQLITE_OK) {

sqlite3_bind_text(statement, 1, [field1Value UTF8String], -1,NULL);

sqlite3_bind_text(statement, 2, [field2Value UTF8String], -1,NULL);

sqlite3_bind_text(statement, 3, [field3Value UTF8String], -1,NULL);

}

if (sqlite3_step(statement) != SQLITE_DONE) {

NSAssert(0, @"插入数据失败！");

sqlite3_finalize(statement);

}

}

//查询数据

- (void)getAllContacts{

NSString *sql = @"SELECT * FROM members";

sqlite3_stmt *statement;

if (sqlite3_prepare_v2(db, [sql UTF8String], -1, &statement, nil) == SQLITE_OK) {

while (sqlite3_step(statement) == SQLITE_ROW) {

char *name = (char *)sqlite3_column_text(statement, 0);

NSString *nameStr = [[NSString alloc] initWithUTF8String:name];

char *email = (char *)sqlite3_column_text(statement, 1);

NSString *emailStr = [[NSString alloc] initWithUTF8String:email];

char *birthday = (char *)sqlite3_column_text(statement, 2);

NSString *birthdayStr = [[NSString alloc] initWithUTF8String:birthday];

NSString *info = [[NSString alloc] initWithFormat:@"%@ - %@ - %@",

nameStr, emailStr, birthdayStr];

NSLog(info);

[nameStr release];

[emailStr release];

[birthdayStr release];

[info release];

}

sqlite3_finalize(statement);

}

}

- (void)viewDidLoad

{

[self openDB];

[self insertRecordIntoTableName:@"members" withField1:@"name" field1Value:@"李1" andField2:@"email" field2Value:@"[email protected]" andField3:@"birthday" field3Value:@"12-45-78"];

[self insertRecordIntoTableName:@"members" withField1:@"name" field1Value:@"李2" andField2:@"email" field2Value:@"[email protected]" andField3:@"birthday" field3Value:@"12-45-78"];

[self insertRecordIntoTableName:@"members" withField1:@"name" field1Value:@"李3" andField2:@"email" field2Value:@"[email protected]" andField3:@"birthday" field3Value:@"12-45-78"];

[self getAllContacts];

sqlite3_close(db);

[super viewDidLoad];

}

@end

插入数据后的效果：

查询的效果：

三、小结：

1.数据查询：sqlite3_exec()函数执行sql语句，在没有返回值的情况下（比如创建表格、插入记录、删除记录等操作中）很好用。

也会用到sqlite3_stat结构、sqlite3_prepare_v2()函数、sqlte3_step()函数和sqlite3_finalize()函数。

查询分三个阶段：准备阶段：sqlite3_stat、sqlite3_prepare_v2()

执行阶段：sqlte3_step()

终止阶段： sqlite3_finalize()

2.附表：

sqlite3数据库打开时的返回值及其所代表的含义