iPhone开发之SQLite的使用

SQLite确实是个好东西，不需要引擎，啥程序都可以使用，特别在嵌入式开发中使用得特别多。

记得刚开始在iPhone中使用SQLite的时候，琢磨了几天，才完成增删改查，费了九牛二虎之力呀。

iPhone中使用SQLite其实也不算简单，链接数据库、执行SQL，都感觉挺复杂的。经过多番研究，将iPhone中SQLite的使用方法封装到一个类中了，增删改查使用起来都极其方便，已经在多个项目中使用了我封装的这个类，目前还没发现有啥bug。

SQLiteOperation.h

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#import <Foundation/Foundation.h>

#import <sqlite3.h>

#import <CoreLocation/CoreLocation.h>

@interface SQLiteOperation : NSObject {

sqlite3 *database;

NSString *path;

}

- (void)readyDatabse;

- (void)getPath;

- (NSMutableArray *)selectData:(NSString *)sql resultColumns:(int)col;

- (BOOL)dealData:(NSString *)sql paramArray:(NSArray *)param;

@end

SQLiteOperation.m

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#import "SQLiteOperation.h"

@implementation SQLiteOperation

#pragma mark 准备数据库

- (void)readyDatabse {

BOOL success;

NSFileManager *fileManager = [NSFileManager defaultManager];

NSError *error;

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

NSString *documentsDirectory = [paths objectAtIndex:0];

NSString *writableDBPath = [documentsDirectory stringByAppendingPathComponent:@"test.sqlite"];

success = [fileManager fileExistsAtPath:writableDBPath];

[self getPath];

if (success) return;

// The writable database does not exist, so copy the default to the appropriate location.

NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"test.sqlite"];

success = [fileManager copyItemAtPath:defaultDBPath toPath:writableDBPath error:&error];

if (!success) {

NSAssert1(0, @"Failed to create writable database file with message '%@'.", [error localizedDescription]);

}

}

#pragma mark 路径

- (void)getPath{

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

NSString *documentsDirectory = [paths objectAtIndex:0];

path = [documentsDirectory stringByAppendingPathComponent:@"test.sqlite"];

}

#pragma mark 查询数据库

/************

sql：sql语句

col：sql语句需要操作的表的所有字段数

***********/

- (NSMutableArray *)selectData:(NSString *)sql resultColumns:(int)col {

[self readyDatabse];

NSMutableArray *returnArray = [[[NSMutableArray alloc] init] autorelease];//所有记录

if (sqlite3_open([path UTF8String], &database) == SQLITE_OK) {

sqlite3_stmt *statement = nil;

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

while (sqlite3_step(statement) == SQLITE_ROW) {

NSMutableArray *row = [[NSMutableArray alloc] init];//一条记录

//NSLog(@"=====%@",statement);

for(int i=0; i<col; i++){

[row addObject:[NSString stringWithFormat:@"%s", sqlite3_column_text(statement, i)]];

}

[returnArray addObject:row];

[row release];

}//end while

}else {

NSLog(@"Error: failed to prepare");

return NO;

}//end if

//NSLog(@"returnArray：%@",returnArray);

return returnArray;

sqlite3_finalize(statement);

} else {

sqlite3_close(database);

NSAssert1(0, @"Failed to open database with message '%s'.", sqlite3_errmsg(database));

}//end if

sqlite3_close(database);

return returnArray;

}

#pragma mark 增，删，改数据库

/************

sql：sql语句

param：sql语句中?对应的值组成的数组

***********/

- (BOOL)dealData:(NSString *)sql paramArray:(NSArray *)param {

[self readyDatabse];

if (sqlite3_open([path UTF8String], &database) == SQLITE_OK) {

sqlite3_stmt *statement = nil;

int success = sqlite3_prepare_v2(database, [sql UTF8String], -1, &statement, NULL);

if (success != SQLITE_OK) {

NSLog(@"Error: failed to prepare");

return NO;

}

//绑定参数

NSInteger max = [param count];

for (int i=0; i<max; i++) {

NSString *temp = [param objectAtIndex:i];

sqlite3_bind_text(statement, i+1, [temp UTF8String], -1, SQLITE_TRANSIENT);

}

success = sqlite3_step(statement);

sqlite3_finalize(statement);

if (success == SQLITE_ERROR) {

NSLog(@"Error: failed to insert into the database");

return NO;

}

}

sqlite3_close(database);

NSLog(@"dealData 成功");

return TRUE;

}

- (void)dealloc{

[path release];

[super dealloc];

}

@end

在此类中将查询写成了一个方法，增、删、改写成了一个方法。

调用起来都灰常简单：

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增

NSArray *paramarray = [[NSArray alloc] initWithObjects:@"Miles", @"28", @"69", nil];

NSString *sql = [[NSString alloc] initWithString:@"INSERT INTO t_test (name, age, score) VALUES (?, ?, ?)"];

[self dealData:sql paramArray:paramarray];

[paramarray release];

[sql release];

删

NSArray *paramarray = [[NSArray alloc] initWithObjects:@"2", nil];

NSString *sql = [[NSString alloc] initWithString:@"DELETE FROM t_test WHERE id=?"];

[self dealData:sql paramArray:paramarray];

[paramarray release];

[sql release];

改

NSArray *paramarray = [[NSArray alloc] initWithObjects:@"Miles", @"30", @"2", nil];

NSString *sql = [[NSString alloc] initWithString:@"UPDATE t_test SET name=?, age=? WHERE id=?"];

[self dealData:sql paramArray:paramarray];

[paramarray release];

[sql release];

查

NSString *sql = [[NSString alloc] initWithString:@"SELECT * FROM t_test WHERE score>0"];

[self selectData:sql resultColumns:4];

[paramarray release];

[sql release];

点击此处下载示例。