iPhone开发之SQLite的运用

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。

DataBaseVC.h

#import &lt;Foundation/Foundation.h&gt;#import &lt;sqlite3.h&gt;#import &lt;CoreLocation/CoreLocation.h&gt;@interface DataBaseVC : NSObject {    sqlite3 *database;NSString *path;}- (void)readyDatabse;- (void)getPath;- (NSMutableArray *)selectData:(NSString *)sql columns:(int)col;- (BOOL)dealData:(NSString *)sql paramarray:(NSArray *)param;@end

DataBaseVC.m

#import "DataBaseVC.h"@implementation DataBaseVC#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 columns:(int)col {[self readyDatabse];NSMutableArray *returndata = [[NSMutableArray alloc] init];//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;//一条记录row = [[NSMutableArray alloc] init];//NSLog(@"=====%@",statement);for(int i=0; i&lt;col; i++){[row addObject:[NSString stringWithFormat:@"%s", sqlite3_column_text(statement, i)]];}[returndata addObject:row];[row release];            }//end while        }else {NSLog(@"Error: failed to prepare");return NO;}//end if//NSLog(@"returndata：%@",returndata);return returndata;        sqlite3_finalize(statement);    } else {        sqlite3_close(database);        NSAssert1(0, @"Failed to open database with message '%s'.", sqlite3_errmsg(database));    }//end ifsqlite3_close(database);return [returndata autorelease];}#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for (int i=0; i&lt;[param count]; i++) {NSString *temp = [param objectAtIndex:i];sqlite3_bind_text(statement, i+1, [temp UTF8String], -1, SQLITE_TRANSIENT);[temp release];}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;}@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：

sqlparam = [NSMutableArray arrayWithObject:lineslastdatedate];sqlstring = [NSMutableString stringWithFormat:@"UPDATE configuration SET LinesLastUpdateDate=?"]; [self dealData:sqlstring paramarray:sqlparam]; 增 NSArray *paramarray = [[NSArray alloc] initWithObjects:@"Miles", @"28", @"69", nil]; NSString *sql = @"INSERT INTO t_test (name, age, score) VALUES (?, ?, ?)"; [self dealData:sql paramarray:paramarray];  删 NSArray *paramarray = [[NSArray alloc] initWithObjects:@"2", nil]; NSString *sql = @"DELETE FROM t_test WHERE id=?"; [self dealData:sql paramarray:paramarray]; 改 NSArray *paramarray = [[NSArray alloc] initWithObjects:@"Miles", @"30", @"2", nil]; NSString *sql = @"UPDATE t_test SET name=?, age=? WHERE id=?"; [self dealData:sql paramarray:paramarray]; 查 NSString *sqls = [NSString stringWithFormat:@"SELECT * FROM t_test WHERE score&gt;%i", 0]; [self selectData:sqls columns:4];

iPhone开发之SQLite的运用

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