{"id":45933,"date":"2026-11-12T13:38:27","date_gmt":"2026-11-12T13:38:27","guid":{"rendered":"https:\/\/www.withdata.com\/blog\/?p=45933"},"modified":"2026-11-12T13:44:09","modified_gmt":"2026-11-12T13:44:09","slug":"get-a-file-out-of-a-blob-column-without-a-script","status":"publish","type":"post","link":"https:\/\/www.withdata.com\/blog\/dbblobeditor\/get-a-file-out-of-a-blob-column-without-a-script.html","title":{"rendered":"Getting a File Out of a BLOB Column Without Writing a Script"},"content":{"rendered":"

The two Stack Overflow questions are years old and very busy: “Script to save varbinary data to disk”<\/em> (121,094 views<\/strong>, 55 votes) and “How to dump a file stored in a sqlite database as a blob”<\/em> (37,133 views<\/strong>, 53 votes). The answers are the same shape in both: write a loop, read the column row by row, write each value to a file, hope the extension is right. It works \u2014 once \u2014 and then it is a script nobody in the team wants to own.<\/p>\n

There is a smaller category next door with even more traffic: “How do I get textual contents from BLOB in Oracle SQL”<\/em> (695,117 views<\/strong>) and “How to query a CLOB column”<\/em> (628,245). Those are about reading<\/em> a value in SQL, and SQL is genuinely the right answer there. The problem starts when the value is a file<\/strong> \u2014 a PDF, a scanned page, a photo \u2014 and what you need is the file back on disk, or a look at it before you decide it is the one.<\/p>\n

1. What “get it out” actually involves<\/h2>\n\n\n\n\n\n\n\n\n
Step<\/th>\nWhat people do today<\/th>\nWhat goes wrong<\/th>\n<\/tr>\n<\/thead>\n
Find the row<\/td>\nSELECT ... WHERE name = '...'<\/code><\/td>\nyou need to know which table\/column holds the LOB<\/td>\n<\/tr>\n
Read the value<\/td>\ndbms_lob.substr<\/code>, substring<\/code>, hex()<\/code>, a client that renders (BLOB)<\/code><\/td>\nthe client shows (BLOB)<\/code> or a wall of hex<\/td>\n<\/tr>\n
Get the bytes out<\/td>\na script (utl_file<\/code>, bcp<\/code>, psycopg2<\/code>, sqlite3<\/code>)<\/td>\nencoding, row size, and the extension you have to guess<\/td>\n<\/tr>\n
Check the result<\/td>\nopen the file<\/td>\nhalf the time the extension is wrong, or the file is truncated<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

A viewer removes three of those four steps: it lists the table, shows the value in a preview, and writes the file with a name and extension you choose.<\/p>\n

2. The GUI route<\/h2>\n

\"DBBlobEditor<\/p>\n

    \n
  1. Log On<\/strong> (toolbar, or File \u2192 Log On<\/em>). Pick the database type \u2014 SQLite, Oracle, SQL Server,<\/li>\n<\/ol>\n

    PostgreSQL, MySQL, DB2 \u2014 and point it at the database (for SQLite, the .db<\/code> file), then Connect<\/strong>.<\/p>\n

      \n
    1. View\/Edit Data<\/strong> opens the table grid: choose the table that holds the LOB column. Rows come up<\/li>\n<\/ol>\n

      with the LOB column marked as a LOB, not as text.<\/p>\n

        \n
      1. Click the LOB cell<\/strong> and the preview opens: images render, PDF pages render, text and XML\/JSON show<\/li>\n<\/ol>\n

        as text, audio and video get a player. This is the step that answers “is this the file I think it is?” without extracting anything.<\/p>\n

        \"DBBlobEditor<\/p>\n

          \n
        1. Export LOB<\/strong> (or Tools \u2192 Export LOB<\/em>) writes the selected value to disk. Export Lob Task<\/strong> does<\/li>\n<\/ol>\n

          the same for a whole table or a query result \u2014 that is the “121k views” script, without the script.<\/p>\n

          A PDF value looks like this in the same preview \u2014 the page itself, not a hex dump:<\/p>\n

          \"DBBlobEditor<\/p>\n

            \n
          1. Import LOB<\/strong> goes the other way: one file, or a folder into many rows, with the file name and<\/li>\n<\/ol>\n

            extension kept in the columns you choose.<\/p>\n

            Measured on a SQLite database with four rows (a PDF, a PNG, a text file, and a NULL):<\/p>\n\n\n\n\n\n\n\n\n
            Step<\/th>\nResult<\/th>\n<\/tr>\n<\/thead>\n
            Log On + pick table<\/td>\nseconds; no client libraries to install<\/td>\n<\/tr>\n
            Preview a PDF row<\/td>\nrenders in the preview pane (pdfium)<\/td>\n<\/tr>\n
            Export one row<\/td>\none dialog: target folder + file name; the extension follows the detected type<\/td>\n<\/tr>\n
            Export a table<\/td>\nExport Lob Task<\/em>: folder + naming pattern, one row per file, log line per row<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

            3. Where the SQL answers still win<\/h2>\n