Sqlite:如何为BLOB强制转换(数据为TEXT) [英] Sqlite: How to cast(data as TEXT) for BLOB
问题描述
我有一个sqlite数据库,要从中提取一列数据类型为BLOB的信息。我正在尝试:
I have a sqlite database from which I want to extract a column of information with the datatype BLOB. I am trying this:
从内容中选择演员(数据为文本)
这显然不起作用。输出是这样的乱码文本:
This is obviously not working. The output is garbled text like this:
x Uak 0? > 8 0Ff;I. 。 i% A s M
内容列中的数据主要是文本,但也可能有图像(我如果我强制转换为TEXT,则可能会导致问题)。我只是想将这些数据提取为可用格式。有任何想法吗?
The data in the content column is mostly text, but may also have images (which I recognized could cause a problem if I cast as TEXT). I simply want to extract that data into a usable format. Any ideas?
推荐答案
您可以使用
SELECT hex(data) FROM content
或
SELECT quote(data) FROM content
第一个将返回一个十六进制字符串( ABCD
),第二个将被引用为SQL文字( X'ABCD'
)。
The first will return a hex string (ABCD
), the second quoted as an SQL literal (X'ABCD'
).
(目前)无法在SQLite中将十六进制列信息转换回BLOB。您将必须使用C / Perl / Python /…绑定来转换和导入这些绑定。
Note that there's (currently) no way of converting hexadecimal column information back to a BLOB in SQLite. You will have to use C/Perl/Python/… bindings to convert and import those.
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