IPhone数据库操作代码例子

//database operation

打开数据库 


-(BOOL) opendatabase{


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

NSString *documentsDirectory = [paths objectAtIndex:0];

NSString *path = [documentsDirectory stringByAppendingPathComponent:@"mydb.sql"];

NSFileManager *fileManager = [NSFileManager defaultManager];

BOOL find = [fileManager fileExistsAtPath:path];

//找到数据库文件mydb.sql

if (find) {

         NSLog(@"Database file have already existed.");

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

         sqlite3_close(database_);

         NSLog(@"Error: open database file.");

         return NO;

        }

         return YES;

}

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

//bFirstCreate_ = YES;

        [self createChannelsTable:database_];//在后面实现函数createChannelsTable

         return YES;

} else {

        sqlite3_close(database_);

        NSLog(@"Error: open database file.");

        return NO;

}

return NO;

}


创建表


- (BOOL) createChannelsTable:(sqlite3*)db{

char *sql = "CREATE TABLE reports (id integer primary key,stime  text,stitle text,scal   text,sruntime text)";

sqlite3_stmt *statement;

if(sqlite3_prepare_v2(db, sql, -1, &statement, nil) != SQLITE_OK) {

         NSLog(@"Error: failed to prepare statement:create reports table");

         return NO;

}

int success = sqlite3_step(statement);

sqlite3_finalize(statement);

if ( success != SQLITE_DONE) {

        NSLog(@"Error: failed to dehydrate:CREATE TABLE reports");

        return NO;

}

NSLog(@"Create table 'reports' successed.");

return YES;

}


插入表 


- (BOOL)insertOneChannel:(NSString*)stime mytitle:(NSString*)stitle mycal:(NSString*)scal myruntime:(NSString*)sruntime

{


sqlite3_stmt *statement;

static char *sql = "INSERT INTO reports (id,stime,stitle,scal,sruntime) VALUES(NULL,?,?,?,?)";

//问号的个数要和(cid,title,imageData,imageLen)里面字段的个数匹配，代表未知的值，将在下面将值和字段关联。

int success = sqlite3_prepare_v2(database_, sql, -1, &statement, NULL);

if (success != SQLITE_OK) {

        NSLog(@"Error: failed to insert:channels");

         return NO;

}

//这里的数字1，2，3，4代表第几个问号

//sqlite3_bind_text(statement, 1, stime, -1, SQLITE_TRANSIENT);

char *p = [stime cStringUsingEncoding:1];

sqlite3_bind_text(statement, 1, [stime cStringUsingEncoding:1], -1, SQLITE_TRANSIENT);

sqlite3_bind_text(statement, 2, [stitle cStringUsingEncoding:1], -1, SQLITE_TRANSIENT);

sqlite3_bind_text(statement, 3, [scal cStringUsingEncoding:1], -1, SQLITE_TRANSIENT);

sqlite3_bind_text(statement, 4, [sruntime cStringUsingEncoding:1], -1, SQLITE_TRANSIENT);


success = sqlite3_step(statement);

sqlite3_finalize(statement);

if (success == SQLITE_ERROR) {

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

        return NO;

}

NSLog(@"Insert One Channel#############:id = _");

return YES;

}

查询表

- (void) getChannels:(NSMutableArray*)fChannels{

sqlite3_stmt *statement = nil;

char *sql = "SELECT * FROM reports";

if (sqlite3_prepare_v2(database_, sql, -1, &statement, NULL) != SQLITE_OK) {

        NSLog(@"Error: failed to prepare statement with message:get channels.");

}

//查询结果集中一条一条的遍历所有的记录，这里的数字对应的是列值。

while (sqlite3_step(statement) == SQLITE_ROW) {

       //char* cid = (char*)sqlite3_column_text(statement, 1);

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

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

       char* scal = (char*)sqlite3_column_text(statement, 3);

       char* sruntime= (char*)sqlite3_column_text(statement, 4);


       //NSString *tmp = [NSString stringWithCString:stitle encoding:1];

        myreportitem* ri = [[myreportitem alloc] init];

       ri.mytime = [NSString stringWithCString:stime encoding:1];

        ri.mytitle = [NSString stringWithCString:stitle encoding:1];

        ri.mycal = [NSString stringWithCString:scal encoding:1];

       ri.myruntime = [NSString stringWithCString:sruntime encoding:1];


       [fChannels addObject:ri];

       [ri release];

}

sqlite3_finalize(statement);

}

删除记录

- (void)doClearReport: {


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

NSString *documentsDirectory = [paths objectAtIndex:0];

NSString *path = [documentsDirectory stringByAppendingPathComponent:@"mydb.sql"];

NSFileManager *fileManager = [NSFileManager defaultManager];

BOOL find = [fileManager fileExistsAtPath:path];

//找到数据库文件mydb.sql

if (find) {

        NSLog(@"Database file have already existed.");

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

        sqlite3_close(database_);

        NSLog(@"Error: open database file.");

        return NO;

      }

      char *sql = "delete from reports";

       sqlite3_stmt *statement;

       if(sqlite3_prepare_v2(database_, sql, -1, &statement, nil) != SQLITE_OK) {

        NSLog(@"Error: failed to prepare statement:create reports table");

       return NO;

     }

     int success = sqlite3_step(statement);

      sqlite3_finalize(statement);

     if ( success != SQLITE_DONE) {

      NSLog(@"Error: failed to dehydrate:delete TABLE reports");

      return NO;

      }

      NSLog(@"Create table 'reports' successed.");


     sqlite3_close(database_);


   }


}