postgresql - 列 "xxxx"的默认值无法自动转换为在 Postgres DB 中键入 bool 值

Question

我正在尝试将 brs.parts 表中的列从字符变化更新为 bool 值。到目前为止，该列的数据为 Y/N。我正在使用以下命令

ALTER TABLE brs.parts ALTER COLUMN is_dpm_scanned TYPE BOOLEAN USING is_dpm_scanned::BOOLEAN

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但是我收到以下错误:

********* 错误 **********

ERROR: default for column "is_dpm_scanned" cannot be cast automatically to type boolean
SQL state: 42804

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表定义是:

CREATE TABLE brs.parts (
    id serial NOT NULL PRIMARY KEY,
    webcrt_part_id INTEGER,
    event_id INTEGER,
    webcrt_job_id INTEGER,
    incoming_serial_number CHARACTER VARYING(256),
    outgoing_serial_number CHARACTER VARYING(256), 
    part_number CHARACTER VARYING(256),
    tag_number NUMERIC,
    is_dpm_scanned CHARACTER VARYING(1) DEFAULT 'N'::CHARACTER VARYING,
    current_operation_id INTEGER,
    creation_date DATE,
    created_by CHARACTER VARYING(20) NOT NULL,
    last_updated_date DATE,
    last_updated_by CHARACTER VARYING(20) NOT NULL,
    is_delete CHARACTER VARYING(1) DEFAULT 'N'::CHARACTER VARYING
);

Answer 1

在更改类型之前必须删除默认约束:

ALTER TABLE parts 
    ALTER COLUMN is_dpm_scanned DROP DEFAULT,
    ALTER COLUMN is_dpm_scanned TYPE BOOLEAN USING is_dpm_scanned::BOOLEAN,
    ALTER COLUMN is_dpm_scanned SET DEFAULT FALSE;

另见:

• Changing a column from string to string array in PostgreSQL以获得详细解释。
• How to cast varchar to boolean .