Flink SQL: UNLOAD Statements

UNLOAD Statements

UNLOAD statements are used to unload a built-in or user-defined module.
UNLOAD语句用于卸载内置或用户定义的模块。

Run a UNLOAD statement

Java
UNLOAD statements can be executed with the executeSql() method of the TableEnvironment. The executeSql() method returns ‘OK’ for a successful LOAD operation; otherwise it will throw an exception.
UNLOAD语句可以使用TableEnvironment的executeSql()方法执行。对于成功的LOAD操作，executeSql()方法返回“OK”；否则将抛出异常。

The following examples show how to run a UNLOAD statement in TableEnvironment.
以下示例演示如何在TableEnvironment中运行UNLOAD语句。

StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
StreamTableEnvironment tEnv = StreamTableEnvironment.create(env);

// unload a core module
tEnv.executeSql("UNLOAD MODULE core");
tEnv.executeSql("SHOW MODULES").print();
// Empty set
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SQL CLI
UNLOAD statements can be executed in SQL CLI.
UNLOAD语句可以在SQL CLI中执行。

The following examples show how to run a UNLOAD statement in SQL CLI.
以下示例显示了如何在SQL CLI中运行UNLOAD语句。

Flink SQL> UNLOAD MODULE core;
[INFO] Unload module succeeded!

Flink SQL> SHOW MODULES;
Empty set
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UNLOAD MODULE

The following grammar gives an overview of the available syntax:
以下语法概述了可用语法：

UNLOAD MODULE module_name
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