RawBLOB
Description
The RawBLOB formats reads all input data to a single value. It is possible to parse only a table with a single field of type String or similar.
The result is output as a binary format without delimiters and escaping. If more than one value is output, the format is ambiguous, and it will be impossible to read the data back.
Raw Formats Comparison
Below is a comparison of the formats RawBLOB and TabSeparatedRaw.
RawBLOB:
- data is output in binary format, no escaping;
- there are no delimiters between values;
- no new-line at the end of each value.
TabSeparatedRaw:
- data is output without escaping;
- the rows contain values separated by tabs;
- there is a line feed after the last value in every row.
The following is a comparison of the RawBLOB and RowBinary formats.
RawBLOB:
- String fields are output without being prefixed by length.
RowBinary:
- String fields are represented as length in varint format (unsigned [LEB128] (https://en.wikipedia.org/wiki/LEB128)), followed by the bytes of the string.
When empty data is passed to the RawBLOB input, ClickHouse throws an exception:
Code: 108. DB::Exception: No data to insert
Example Usage
Query
$ clickhouse-client --query "CREATE TABLE {some_table} (a String) ENGINE = Memory;"
$ cat {filename} | clickhouse-client --query="INSERT INTO {some_table} FORMAT RawBLOB"
$ clickhouse-client --query "SELECT * FROM {some_table} FORMAT RawBLOB" | md5sum
Response
f9725a22f9191e064120d718e26862a9 -