在iOS中从sqlite数据库存储和检索图像 [英] Storing and retrieving image from sqlite database in iOS

问题描述

- (void)viewDidLoad {
    [super viewDidLoad];
    [self createDB];
}

-(void)createDB {
    NSArray *path = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *docdir = [path objectAtIndex:0]; //path[0];
    dbpath = [docdir stringByAppendingPathComponent:@"arun.sqlite"];
    NSLog(@"database path : %@",dbpath);

    NSFileManager *filemgr = [NSFileManager defaultManager];
    if ([filemgr fileExistsAtPath:dbpath] == NO) {
        //OPEN AND CREATE DATABASE
        if (sqlite3_open([dbpath UTF8String], &myDB) == SQLITE_OK) {
            //CREATE TABLE
            NSString *createSQL = @"CREATE TABLE IF NOT EXISTS STUDENT (ID INTEGER PRIMARY KEY AUTOINCREMENT, NAME TEXT, ADDRESS TEXT, ROLLNO INTEGER,IMAGE BLOB)";

            char *error = nil;
            if (sqlite3_exec(myDB, [createSQL UTF8String] , NULL, NULL, &error) == SQLITE_OK) {
                NSLog(@"Database and tables created.");
            } else {
                  NSLog(@"Error %s",error);
            }

            sqlite3_close(myDB);
        }
    }
}

- (void)saveImage {
    sqlite3_stmt *compiledStmt;
    sqlite3 *db;
    if(sqlite3_open([dbpath UTF8String], &db)==SQLITE_OK) {
        NSString *insertSQL = [NSString stringWithFormat:@"INSERT INTO STUDENT (ROLLNO,IMAGE) VALUES(\"%@\", \"%@\")", rollnoTxt.text, selectImgvw.image];
        if(sqlite3_prepare_v2(db,[insertSQL cStringUsingEncoding:NSUTF8StringEncoding], -1, &compiledStmt, NULL) == SQLITE_OK){
            UIImage *image = selectImgvw.image;
            NSData *imgdata = UIImagePNGRepresentation(image);

            sqlite3_bind_blob(compiledStmt, 1, [imgdata bytes], (int)[imgdata length], SQLITE_TRANSIENT);

            if(sqlite3_step(compiledStmt) != SQLITE_DONE ) {
                NSLog( @"Error: %s", sqlite3_errmsg(db) );
            } else {
                NSLog( @"Insert into row id = %lld", (sqlite3_last_insert_rowid(db)));
            }

            sqlite3_finalize(compiledStmt);
        }
    }
    sqlite3_close(db);
}


- (void)showImage {
    sqlite3_stmt *compiledStmt;
    sqlite3 *db;
    if(sqlite3_open([dbpath UTF8String], &db)==SQLITE_OK){
        NSString *insertSQL = [NSString stringWithFormat:@"SELECT IMAGE FROM STUDENT WHERE ROLLNO = %@",rollnoTxt.text];
        if(sqlite3_prepare_v2(db,[insertSQL cStringUsingEncoding:NSUTF8StringEncoding], -1, &compiledStmt, NULL) == SQLITE_OK) {
            while(sqlite3_step(compiledStmt) == SQLITE_ROW) {
                int length = sqlite3_column_bytes(compiledStmt, 0);
                NSData *imgdata = [NSData dataWithBytes:sqlite3_column_blob(compiledStmt, 0) length:length];

                NSLog(@"Length : %ld", [imgdata length]);

                if(imgdata == nil)
                    NSLog(@"No image found.");
                else {
                    UIImage *img = [UIImage imageWithData:imgdata];
                    displayImgvw.image = img;
                }
            }
        }
        sqlite3_finalize(compiledStmt);
    }
    sqlite3_close(db);
}

以上是我的代码片段.图像被保存到 SQLiteDataBase 但问题是在获取图像时，我在图像视图中没有得到任何值.我已经做了一段时间了.做了更多的研究，但无法解决它.如果有人能解决这个问题，请给我建议.

Above is my code snippet. Image is saved to SQLiteDataBase but the problem is that while fetching the image, I am not getting any value when feed to image view. I have been doing for a while. Did more research but could not solve it. Please suggest me if anyone can solve this.

推荐答案

您尝试将完整图像存储在数据库中.

You try to store full image in Database.

但是如果您将图像存储在文档目录路径中.

But if you store image in Document Directory Path.

这个路径存储到数据库.

And this path store to database.

然后很容易存储和检索图像.

Then it's easy to store and retrieve Image.

下面是我的代码.

用于在文档目录路径

 NSString *pathsToReources = [[NSBundle mainBundle] resourcePath];
NSString *yourOriginalDatabasePath = [pathsToReources stringByAppendingPathComponent:@"Demo.sqlite"];
NSArray *pathsToDocuments =NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [pathsToDocuments objectAtIndex: 0];

NSString *dbPath = [documentsDirectory stringByAppendingPathComponent:@"Demo.sqlite"];
if (![[NSFileManager defaultManager] isReadableFileAtPath: dbPath]) {
    if ([[NSFileManager defaultManager] copyItemAtPath: yourOriginalDatabasePath toPath: dbPath error: NULL] != YES)
        NSAssert2(0, @"Fail to copy database from %@ to %@", yourOriginalDatabasePath, dbPath);
}

databasePath = [[NSString alloc]initWithString: [NSString stringWithFormat:@"%@",dbPath]];

const char *dbpath = [databasePath UTF8String];
sqlite3_stmt *statement;
NSString * timestamp = [NSString stringWithFormat:@"%f.png",[[NSDate date] timeIntervalSince1970] * 1000];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
NSString *documentsPath = [paths objectAtIndex:0];
NSString *smallpath=[NSString stringWithFormat:@"%@/%@",documentsPath,timestamp];

if(sqlite3_open(dbpath, &contactDB)==SQLITE_OK)
{

    NSString *insertSQL = [NSString stringWithFormat:@"insert into Test values('%@','%@')",txtname.text,smallpath];
    //img
    UIImage *img11=img1.image;
    NSData *data = (UIImageJPEGRepresentation(img11,1.0));
    [data writeToFile:smallpath atomically:YES];
    const char *inser_stmt=[insertSQL UTF8String];
    sqlite3_prepare_v2(contactDB, inser_stmt, -1, &statement, NULL);
    if (sqlite3_step(statement) == SQLITE_DONE)
    {
        NSLog(@"Company Detail insert succesfully");

    }
    else
    {
        //self.status.text = @"Failed to add contact";
    }
    sqlite3_finalize(statement);
    sqlite3_close(contactDB);
}

else
{
}

用于检索图像

 NSString *pathsToReources = [[NSBundle mainBundle] resourcePath];
NSString *yourOriginalDatabasePath = [pathsToReources stringByAppendingPathComponent:@"Demo.sqlite"];
NSArray *pathsToDocuments = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [pathsToDocuments objectAtIndex: 0];

NSString *dbPath = [documentsDirectory stringByAppendingPathComponent:@"Demo.sqlite"];
if (![[NSFileManager defaultManager] isReadableFileAtPath: dbPath]) {
    if ([[NSFileManager defaultManager] copyItemAtPath: yourOriginalDatabasePath toPath: dbPath error: NULL] != YES)
        NSAssert2(0, @"Fail to copy database from %@ to %@", yourOriginalDatabasePath, dbPath);
}

databasePath = [[NSString alloc]initWithString: [NSString stringWithFormat:@"%@",dbPath]];

const char *dbpath = [databasePath UTF8String];
sqlite3_stmt *statement;

if (sqlite3_open(dbpath, &_database) == SQLITE_OK)
{
    NSString *querySQL = [NSString stringWithFormat: @"SELECT Name,image FROM Test"];
    const char *query_stmt = [querySQL UTF8String];

    if (sqlite3_prepare_v2(_database, query_stmt, -1, &statement, NULL) == SQLITE_OK)
    {
        arrimage = [[NSMutableArray alloc] init];
        arrname = [[NSMutableArray alloc] init];

        while (sqlite3_step(statement) == SQLITE_ROW)
        {

            [arrname addObject:[NSString stringWithUTF8String:(char *)sqlite3_column_text(statement,0)]];
            [arrimage addObject:[NSString stringWithUTF8String:(char *)sqlite3_column_text(statement,1)]];

        }
        sqlite3_finalize(statement);
    }
    sqlite3_close(_database);
    [tblobj reloadData];
}

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