SQL/JDBC 中的内联 BLOB/BINARY 数据类型 [英] Inline BLOB / BINARY data types in SQL / JDBC

问题描述

假设我想避免在 JDBC 中使用绑定变量并使用ad-hoc"语句运行 SQL，例如:

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 ...");

是否有任何约定/JDBC 转义语法来内联 BLOB 数据类型?我知道 H2 有这种语法:

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');

但这不是标准.有什么通用的解决方案吗?请注意，我对一般方法感兴趣.我知道这可能会变得非常低效.

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.

推荐答案

可能没有 JDBC 转义语法，所以我搜索了一下，发现并成功测试了以下内容:

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

• SQL Server, Sybase ASE, Sybase SQL Anywhere

INSERT INTO lob_table VALUES (0x01FF);

DB2

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

Derby, H2, HSQLDB, Ingres, MySQL, SQLite

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

甲骨文

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

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);

请参阅 AH 的答案了解更多信息Postgres 的十六进制编码细节

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

SQL 标准

-- 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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