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Inline BLOB / BINARY data types in SQL / JDBC

Let's say I want to avoid using bind variables in JDBC and run SQL using "ad-hoc" statements, e.g:

connection.createStatement().executeQuery("SELECT ...");

Is there any convention / JDBC escape syntax to inline BLOB data types? I know that H2 has this syntax:

INSERT INTO lob_table VALUES (X'01FF');

But that's not a standard. Any general solutions? Note, I'm interested in a general approach. I know that this can turn out to be terribly inefficient.

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Lukas Eder Avatar asked Feb 16 '12 22:02

Lukas Eder


2 Answers

There probably isn't a JDBC escape syntax, so I searched around a bit and found and successfully tested the following:

  • SQL Server, Sybase ASE, Sybase SQL Anywhere

    INSERT INTO lob_table VALUES (0x01FF);
    
  • DB2

    -- Use a blob constructor. This is not needed for VARCHAR FOR BIT DATA types
    INSERT INTO lob_table VALUES (blob(X'01FF'));
    
  • Derby, H2, HSQLDB, Ingres, MySQL, SQLite

    INSERT INTO lob_table VALUES (X'01FF');
    
  • Oracle

    -- As mentioned by a_horse_with_no_name, keep in mind the relatively low
    -- limitation of Oracle's VARCHAR types to hold only 4000 bytes!
    INSERT INTO lob_table VALUES (hextoraw('01FF'));
    
  • Postgres

    -- There is also hex encoding as of Postgres 9.0
    -- The explicit cast is important, though
    INSERT INTO lob_table VALUES (E'\\001\\377'::bytea);
    

    See A.H.'s answer for more details about Postgres' hex encoding

  • SQL Standard

    -- SQL actually defines binary literals as such 
    -- (as implemented by DB2, Derby, H2, HSQLDB, Ingres, MySQL, SQLite):
    <binary string literal> ::=
      X <quote> [ <space>... ] 
      [ { <hexit> [ <space>... ] <hexit> [ <space>... ] }... ] <quote>
    
    <hexit> ::=
      <digit> | A | B | C | D | E | F | a | b | c | d | e | f
    
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Lukas Eder Avatar answered Oct 14 '22 16:10

Lukas Eder


I'd like to add some PostgreSQL specific stuff to Lukas' answer:

The shortest and most easiest solution would be (since PostgreSQL 9.0 at least):

insert into lob_table (data) values( E'\\x0102030405FF' )

without any cast (if the column is already a bytea one) and only one \\x mark right at the beginning. This is the "hex format" documented in the section Binary Data Types.

Regarding the X'01FF' syntax: According to the string constant documentation PostgreSQL does support it - for bit strings. And it seems, that there is no standard conversion from bit to bytea.

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A.H. Avatar answered Oct 14 '22 18:10

A.H.