数据库迁移执行Liquibase时遇ORA-01704字符串过长错误

Ah, that classic Oracle string length issue biting you when using Liquibase! The problem here is that when you stick a string longer than 4000 characters directly into the value attribute of a <column> tag, Liquibase passes it as a literal string to Oracle, which hits the VARCHAR2 literal limit. Here are three solid ways to fix this:

1. Use a <sql> tag with bind variables (recommended) #

This bypasses XML parsing limitations and leverages Oracle's native handling of CLOBs via bind parameters—plus it avoids SQL injection risks:

<changeSet id="insert_long_customer_text" author="your_username">
  <sql>
    INSERT INTO ORG_CUSTOMER ("My-Column")
    VALUES (TO_CLOB(?))
    <param value="a very long string that goes on and on and... (way over 4000 chars)" />
  </sql>
</changeSet>

2. Swap value for valueClob in the <column> tag #

Liquibase has a dedicated attribute for CLOB values that tells it to handle the string as a large object instead of a regular literal:

<insert tableName="ORG_CUSTOMER">
  <column name="My-Column" valueClob="a very long string...."/>
</insert>

Important: Make sure your target column is actually a CLOB (or NCLOB) type. If it's still a VARCHAR2, Oracle will truncate the data even if Liquibase sends it correctly—so you'll need to alter the column first if needed.

3. Load the long text from an external file #

For extra-long strings (think tens of thousands of characters), storing the content in a separate text file keeps your changelog clean and avoids XML parsing headaches:

<insert tableName="ORG_CUSTOMER">
  <column name="My-Column" valueClobFile="./data/long_customer_text.txt"/>
</insert>

The path can be relative to your changelog file or an absolute path—just make sure Liquibase can access the file when running your update command.

Bonus: Adjust your column type if needed #

If your My-Column is still a VARCHAR2, you'll need to modify it to CLOB first to hold the long data:

<changeSet id="convert_column_to_clob" author="your_username">
  <modifyDataType tableName="ORG_CUSTOMER" columnName="My-Column" newDataType="CLOB"/>
</changeSet>

Run this changeSet before your insert to avoid truncation issues.

Also, double-check that you're using a recent Oracle JDBC driver (ojdbc8 or newer)—older versions had quirks with CLOB handling that could cause unexpected errors.

内容的提问来源于stack exchange，提问作者Benny