选择查询在 SQLite 中不起作用

Question

我正在运行一个包含选择查询的方法，但是编译的语句不起作用，断点跳过它声明它的行，当我将光标放在它上面时它没有显示任何值，这是我正在使用的代码：

-(NSMutableArray *)GetAllPartsName
{
    NSString *path = [self getDBPath];
    // Open the database from the users filessytem

    NSMutableArray *Parts=[[[NSMutableArray alloc]init]autorelease ];
    if(sqlite3_open([path UTF8String], &database) == SQLITE_OK) {
        // Setup the SQL Statement and compile it for faster access

        NSString *sqlQuery = [NSString stringWithFormat:@"SELECT Parts_Name FROM Parts"];
        NSLog(@"%@",sqlQuery);
        const char *sqlStatement = [sqlQuery UTF8String]; 
        //The break point skips the sqlite3_stmt.
        sqlite3_stmt *compiledStatement;
        //when i put the cursor over compiledStatement it shows no value
        if(sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) {
            // Loop through the results and add them to the feeds array
            while(sqlite3_step(compiledStatement) == SQLITE_ROW) {
                // Read the data from the result row
                NSMutableDictionary *PositionDict=[[NSMutableDictionary alloc]init];
                //setting the parts into dictionary
                [PositionDict setObject:[NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement,0)] forKey:@"Parts_Name"];
                [Parts addObject:PositionDict];
                NSLog(@"%@",PositionDict);
                [PositionDict release];
            }
        }
        // Release the compiled statement from memory
        sqlite3_finalize(compiledStatement);
    }
    sqlite3_close(database);
    return Parts;
}

Answer 1

试试 FMDattabase (https://github.com/ccgus/fmdb)

基本：

    FMDatabase *_db = [[FMDatabase databaseWithPath:[[self class] databaseFilePath]] retain];
    [_db open];

NSMutableArray *emails = [[NSMutableArray alloc] init];
NSString * query = [NSString stringWithFormat:@"SELECT `email` FROM `email`"];
FMResultSet * result = [_db executeQuery:query];
while ([result next]) 
{
    [emails addObject:[result stringForColumn:@"email"]];
}
return [emails autorelease];