Reference
Version · 6.0
Change Automation Reference

alterStandardTableColumn

Last updated: August 12, 2026

Modifies column properties on an existing Snowflake standard table.

Available attributes

Attribute	Type	Description	Required
`catalogName`	String	Name of the catalog (database) containing the table	No
`schemaName`	String	Name of the schema containing the table	No
`tableName`	String	Name of the table containing the column	Yes
`columnName`	String	Name of the column to alter	Yes
`ifExists`	Boolean	Only execute if the table exists	No

Nullable

Controls the NOT NULL constraint on the column.

alterNullable nested attributes

Attribute	Type	Description	Required
`setNotNull`	Boolean	If true, adds NOT NULL constraint	No*
`dropNotNull`	Boolean	If true, removes NOT NULL constraint	No*

*Exactly one of setNotNull or dropNotNull must be true.

<?xml version="1.0" encoding="UTF-8"?>
<databaseChangeLog
        xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
        xmlns:pro-snowflake="http://www.liquibase.org/xml/ns/pro-snowflake"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
        http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd
        http://www.liquibase.org/xml/ns/pro-snowflake
        http://www.liquibase.org/xml/ns/pro-snowflake/liquibase-pro-snowflake-latest.xsd">

    <!-- Add NOT NULL constraint -->
    <changeSet id="add-not-null" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="MY_TABLE" columnName="MY_COLUMN">
            <pro-snowflake:alterNullable setNotNull="true"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

    <!-- Remove NOT NULL constraint -->
    <changeSet id="drop-not-null" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="MY_TABLE" columnName="MY_COLUMN">
            <pro-snowflake:alterNullable dropNotNull="true"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

</databaseChangeLog>

databaseChangeLog:
  # Add NOT NULL constraint
  - changeSet:
      id: add-not-null
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: MY_TABLE
            columnName: MY_COLUMN
            alterNullable:
              setNotNull: true

  # Remove NOT NULL constraint
  - changeSet:
      id: drop-not-null
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: MY_TABLE
            columnName: MY_COLUMN
            alterNullable:
              dropNotNull: true

{
  "databaseChangeLog": [
    {
      "changeSet": {
        "id": "add-not-null",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "MY_TABLE",
              "columnName": "MY_COLUMN",
              "alterNullable": {
                "setNotNull": true
              }
            }
          }
        ]
      }
    },
    {
      "changeSet": {
        "id": "drop-not-null",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "MY_TABLE",
              "columnName": "MY_COLUMN",
              "alterNullable": {
                "dropNotNull": true
              }
            }
          }
        ]
      }
    }
  ]
}

--liquibase formatted sql

--changeset examples:add-not-null-constraint
-- Add NOT NULL constraint
ALTER TABLE MY_TABLE MODIFY COLUMN MY_COLUMN SET NOT NULL;

--changeset examples:remove-not-null-constraint
-- Remove NOT NULL constraint
ALTER TABLE MY_TABLE MODIFY COLUMN MY_COLUMN DROP NOT NULL;

<?xml version="1.0" encoding="UTF-8"?>
<databaseChangeLog
        xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
        xmlns:pro-snowflake="http://www.liquibase.org/xml/ns/pro-snowflake"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
        http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd
        http://www.liquibase.org/xml/ns/pro-snowflake
        http://www.liquibase.org/xml/ns/pro-snowflake/liquibase-pro-snowflake-latest.xsd">

    <!-- Add NOT NULL constraint -->
    <changeSet id="add-not-null" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="MY_TABLE" columnName="MY_COLUMN">
            <pro-snowflake:alterNullable setNotNull="true"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

    <!-- Remove NOT NULL constraint -->
    <changeSet id="drop-not-null" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="MY_TABLE" columnName="MY_COLUMN">
            <pro-snowflake:alterNullable dropNotNull="true"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

</databaseChangeLog>

databaseChangeLog:
  # Add NOT NULL constraint
  - changeSet:
      id: add-not-null
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: MY_TABLE
            columnName: MY_COLUMN
            alterNullable:
              setNotNull: true

  # Remove NOT NULL constraint
  - changeSet:
      id: drop-not-null
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: MY_TABLE
            columnName: MY_COLUMN
            alterNullable:
              dropNotNull: true

{
  "databaseChangeLog": [
    {
      "changeSet": {
        "id": "add-not-null",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "MY_TABLE",
              "columnName": "MY_COLUMN",
              "alterNullable": {
                "setNotNull": true
              }
            }
          }
        ]
      }
    },
    {
      "changeSet": {
        "id": "drop-not-null",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "MY_TABLE",
              "columnName": "MY_COLUMN",
              "alterNullable": {
                "dropNotNull": true
              }
            }
          }
        ]
      }
    }
  ]
}

--liquibase formatted sql

--changeset examples:add-not-null-constraint
-- Add NOT NULL constraint
ALTER TABLE MY_TABLE MODIFY COLUMN MY_COLUMN SET NOT NULL;

--changeset examples:remove-not-null-constraint
-- Remove NOT NULL constraint
ALTER TABLE MY_TABLE MODIFY COLUMN MY_COLUMN DROP NOT NULL;

Data type

Changes the column data type. Snowflake supports increasing precision or length for compatible types.

alterDataType nested attributes

Attribute	Type	Description	Required
`newDataType`	String	The new data type	Yes

<?xml version="1.0" encoding="UTF-8"?>
<databaseChangeLog
        xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
        xmlns:pro-snowflake="http://www.liquibase.org/xml/ns/pro-snowflake"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
        http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd
        http://www.liquibase.org/xml/ns/pro-snowflake
        http://www.liquibase.org/xml/ns/pro-snowflake/liquibase-pro-snowflake-latest.xsd">

    <!-- Increase VARCHAR length -->
    <changeSet id="increase-varchar-length" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="MY_TABLE" columnName="MY_COLUMN">
            <pro-snowflake:alterDataType newDataType="VARCHAR(500)"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

</databaseChangeLog>

databaseChangeLog:
  - changeSet:
      id: increase-varchar-length
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: MY_TABLE
            columnName: MY_COLUMN
            alterDataType:
              newDataType: VARCHAR(500)

{
  "databaseChangeLog": [
    {
      "changeSet": {
        "id": "increase-varchar-length",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "MY_TABLE",
              "columnName": "MY_COLUMN",
              "alterDataType": {
                "newDataType": "VARCHAR(500)"
              }
            }
          }
        ]
      }
    }
  ]
}

ALTER TABLE MY_TABLE MODIFY COLUMN MY_COLUMN SET DATA TYPE VARCHAR(500);

<?xml version="1.0" encoding="UTF-8"?>
<databaseChangeLog
        xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
        xmlns:pro-snowflake="http://www.liquibase.org/xml/ns/pro-snowflake"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
        http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd
        http://www.liquibase.org/xml/ns/pro-snowflake
        http://www.liquibase.org/xml/ns/pro-snowflake/liquibase-pro-snowflake-latest.xsd">

    <!-- Increase VARCHAR length -->
    <changeSet id="increase-varchar-length" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="MY_TABLE" columnName="MY_COLUMN">
            <pro-snowflake:alterDataType newDataType="VARCHAR(500)"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

</databaseChangeLog>

databaseChangeLog:
  - changeSet:
      id: increase-varchar-length
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: MY_TABLE
            columnName: MY_COLUMN
            alterDataType:
              newDataType: VARCHAR(500)

{
  "databaseChangeLog": [
    {
      "changeSet": {
        "id": "increase-varchar-length",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "MY_TABLE",
              "columnName": "MY_COLUMN",
              "alterDataType": {
                "newDataType": "VARCHAR(500)"
              }
            }
          }
        ]
      }
    }
  ]
}

ALTER TABLE MY_TABLE MODIFY COLUMN MY_COLUMN SET DATA TYPE VARCHAR(500);

Default value

Sets or drops the default value for a column. Note: Snowflake only supports SET DEFAULT for sequence-based defaults.

alterDefault nested attributes

Attribute	Type	Description	Required
`newSequenceDefault`	String	Sequence expression (e.g., SEQ.NEXTVAL)	No*
`dropDefault`	Boolean	If true, drops the default value	No*

*Exactly one of newSequenceDefault or dropDefault must be specified.

<?xml version="1.0" encoding="UTF-8"?>
<databaseChangeLog
        xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
        xmlns:pro-snowflake="http://www.liquibase.org/xml/ns/pro-snowflake"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
        http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd
        http://www.liquibase.org/xml/ns/pro-snowflake
        http://www.liquibase.org/xml/ns/pro-snowflake/liquibase-pro-snowflake-latest.xsd">

    <!-- Set sequence default -->
    <changeSet id="set-sequence-default" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="MY_TABLE" columnName="ID">
            <pro-snowflake:alterDefault newSequenceDefault="MY_SCHEMA.MY_SEQ.NEXTVAL"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

    <!-- Drop default -->
    <changeSet id="drop-default" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="MY_TABLE" columnName="ID">
            <pro-snowflake:alterDefault dropDefault="true"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

</databaseChangeLog>

databaseChangeLog:
  # Set sequence default
  - changeSet:
      id: set-sequence-default
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: MY_TABLE
            columnName: ID
            alterDefault:
              newSequenceDefault: MY_SCHEMA.MY_SEQ.NEXTVAL

  # Drop default
  - changeSet:
      id: drop-default
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: MY_TABLE
            columnName: ID
            alterDefault:
              dropDefault: true

{
  "databaseChangeLog": [
    {
      "changeSet": {
        "id": "set-sequence-default",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "MY_TABLE",
              "columnName": "ID",
              "alterDefault": {
                "newSequenceDefault": "MY_SCHEMA.MY_SEQ.NEXTVAL"
              }
            }
          }
        ]
      }
    },
    {
      "changeSet": {
        "id": "drop-default",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "MY_TABLE",
              "columnName": "ID",
              "alterDefault": {
                "dropDefault": true
              }
            }
          }
        ]
      }
    }
  ]
}

-- Set sequence default
ALTER TABLE MY_TABLE MODIFY COLUMN ID SET DEFAULT MY_SCHEMA.MY_SEQ.NEXTVAL;

-- Drop default
ALTER TABLE MY_TABLE MODIFY COLUMN ID DROP DEFAULT;

<?xml version="1.0" encoding="UTF-8"?>
<databaseChangeLog
        xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
        xmlns:pro-snowflake="http://www.liquibase.org/xml/ns/pro-snowflake"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
        http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd
        http://www.liquibase.org/xml/ns/pro-snowflake
        http://www.liquibase.org/xml/ns/pro-snowflake/liquibase-pro-snowflake-latest.xsd">

    <!-- Set sequence default -->
    <changeSet id="set-sequence-default" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="MY_TABLE" columnName="ID">
            <pro-snowflake:alterDefault newSequenceDefault="MY_SCHEMA.MY_SEQ.NEXTVAL"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

    <!-- Drop default -->
    <changeSet id="drop-default" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="MY_TABLE" columnName="ID">
            <pro-snowflake:alterDefault dropDefault="true"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

</databaseChangeLog>

databaseChangeLog:
  # Set sequence default
  - changeSet:
      id: set-sequence-default
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: MY_TABLE
            columnName: ID
            alterDefault:
              newSequenceDefault: MY_SCHEMA.MY_SEQ.NEXTVAL

  # Drop default
  - changeSet:
      id: drop-default
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: MY_TABLE
            columnName: ID
            alterDefault:
              dropDefault: true

{
  "databaseChangeLog": [
    {
      "changeSet": {
        "id": "set-sequence-default",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "MY_TABLE",
              "columnName": "ID",
              "alterDefault": {
                "newSequenceDefault": "MY_SCHEMA.MY_SEQ.NEXTVAL"
              }
            }
          }
        ]
      }
    },
    {
      "changeSet": {
        "id": "drop-default",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "MY_TABLE",
              "columnName": "ID",
              "alterDefault": {
                "dropDefault": true
              }
            }
          }
        ]
      }
    }
  ]
}

-- Set sequence default
ALTER TABLE MY_TABLE MODIFY COLUMN ID SET DEFAULT MY_SCHEMA.MY_SEQ.NEXTVAL;

-- Drop default
ALTER TABLE MY_TABLE MODIFY COLUMN ID DROP DEFAULT;

Masking policy

Sets or unsets a masking policy on the column.

alterMaskingPolicy nested attributes

Attribute	Type	Description	Required
`policyName`	String	Name of the masking policy to apply	No*
`using`	String	Additional columns for conditional masking	No
`force`	Boolean	If true, forces policy replacement	No
`unsetPolicy`	Boolean	If true, removes the masking policy	No*

*Specify either policyName to set or unsetPolicy to remove.

<?xml version="1.0" encoding="UTF-8"?>
<databaseChangeLog
        xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
        xmlns:pro-snowflake="http://www.liquibase.org/xml/ns/pro-snowflake"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
        http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd
        http://www.liquibase.org/xml/ns/pro-snowflake
        http://www.liquibase.org/xml/ns/pro-snowflake/liquibase-pro-snowflake-latest.xsd">

    <!-- Set masking policy -->
    <changeSet id="set-masking-policy" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="CUSTOMERS" columnName="EMAIL">
            <pro-snowflake:alterMaskingPolicy policyName="EMAIL_MASK" force="true"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

    <!-- Set masking policy with conditional columns -->
    <changeSet id="set-masking-policy-conditional" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="CUSTOMERS" columnName="SSN">
            <pro-snowflake:alterMaskingPolicy
                policyName="SSN_MASK"
                using="ROLE_COLUMN"
                force="true"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

    <!-- Unset masking policy -->
    <changeSet id="unset-masking-policy" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="CUSTOMERS" columnName="EMAIL">
            <pro-snowflake:alterMaskingPolicy unsetPolicy="true"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

</databaseChangeLog>

databaseChangeLog:
  # Set masking policy
  - changeSet:
      id: set-masking-policy
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: CUSTOMERS
            columnName: EMAIL
            alterMaskingPolicy:
              policyName: EMAIL_MASK
              force: true

  # Set masking policy with conditional columns
  - changeSet:
      id: set-masking-policy-conditional
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: CUSTOMERS
            columnName: SSN
            alterMaskingPolicy:
              policyName: SSN_MASK
              using: ROLE_COLUMN
              force: true

  # Unset masking policy
  - changeSet:
      id: unset-masking-policy
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: CUSTOMERS
            columnName: EMAIL
            alterMaskingPolicy:
              unsetPolicy: true

{
  "databaseChangeLog": [
    {
      "changeSet": {
        "id": "set-masking-policy",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "CUSTOMERS",
              "columnName": "EMAIL",
              "alterMaskingPolicy": {
                "policyName": "EMAIL_MASK",
                "force": true
              }
            }
          }
        ]
      }
    },
    {
      "changeSet": {
        "id": "set-masking-policy-conditional",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "CUSTOMERS",
              "columnName": "SSN",
              "alterMaskingPolicy": {
                "policyName": "SSN_MASK",
                "using": "ROLE_COLUMN",
                "force": true
              }
            }
          }
        ]
      }
    },
    {
      "changeSet": {
        "id": "unset-masking-policy",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "CUSTOMERS",
              "columnName": "EMAIL",
              "alterMaskingPolicy": {
                "unsetPolicy": true
              }
            }
          }
        ]
      }
    }
  ]
}

-- Set masking policy
ALTER TABLE CUSTOMERS MODIFY COLUMN EMAIL SET MASKING POLICY EMAIL_MASK FORCE;

-- Set masking policy with conditional columns
ALTER TABLE CUSTOMERS MODIFY COLUMN SSN SET MASKING POLICY SSN_MASK USING (SSN, ROLE_COLUMN) FORCE;

-- Unset masking policy
ALTER TABLE CUSTOMERS MODIFY COLUMN EMAIL UNSET MASKING POLICY;

<?xml version="1.0" encoding="UTF-8"?>
<databaseChangeLog
        xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
        xmlns:pro-snowflake="http://www.liquibase.org/xml/ns/pro-snowflake"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
        http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd
        http://www.liquibase.org/xml/ns/pro-snowflake
        http://www.liquibase.org/xml/ns/pro-snowflake/liquibase-pro-snowflake-latest.xsd">

    <!-- Set masking policy -->
    <changeSet id="set-masking-policy" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="CUSTOMERS" columnName="EMAIL">
            <pro-snowflake:alterMaskingPolicy policyName="EMAIL_MASK" force="true"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

    <!-- Set masking policy with conditional columns -->
    <changeSet id="set-masking-policy-conditional" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="CUSTOMERS" columnName="SSN">
            <pro-snowflake:alterMaskingPolicy
                policyName="SSN_MASK"
                using="ROLE_COLUMN"
                force="true"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

    <!-- Unset masking policy -->
    <changeSet id="unset-masking-policy" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="CUSTOMERS" columnName="EMAIL">
            <pro-snowflake:alterMaskingPolicy unsetPolicy="true"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

</databaseChangeLog>

databaseChangeLog:
  # Set masking policy
  - changeSet:
      id: set-masking-policy
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: CUSTOMERS
            columnName: EMAIL
            alterMaskingPolicy:
              policyName: EMAIL_MASK
              force: true

  # Set masking policy with conditional columns
  - changeSet:
      id: set-masking-policy-conditional
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: CUSTOMERS
            columnName: SSN
            alterMaskingPolicy:
              policyName: SSN_MASK
              using: ROLE_COLUMN
              force: true

  # Unset masking policy
  - changeSet:
      id: unset-masking-policy
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: CUSTOMERS
            columnName: EMAIL
            alterMaskingPolicy:
              unsetPolicy: true

{
  "databaseChangeLog": [
    {
      "changeSet": {
        "id": "set-masking-policy",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "CUSTOMERS",
              "columnName": "EMAIL",
              "alterMaskingPolicy": {
                "policyName": "EMAIL_MASK",
                "force": true
              }
            }
          }
        ]
      }
    },
    {
      "changeSet": {
        "id": "set-masking-policy-conditional",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "CUSTOMERS",
              "columnName": "SSN",
              "alterMaskingPolicy": {
                "policyName": "SSN_MASK",
                "using": "ROLE_COLUMN",
                "force": true
              }
            }
          }
        ]
      }
    },
    {
      "changeSet": {
        "id": "unset-masking-policy",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "CUSTOMERS",
              "columnName": "EMAIL",
              "alterMaskingPolicy": {
                "unsetPolicy": true
              }
            }
          }
        ]
      }
    }
  ]
}

-- Set masking policy
ALTER TABLE CUSTOMERS MODIFY COLUMN EMAIL SET MASKING POLICY EMAIL_MASK FORCE;

-- Set masking policy with conditional columns
ALTER TABLE CUSTOMERS MODIFY COLUMN SSN SET MASKING POLICY SSN_MASK USING (SSN, ROLE_COLUMN) FORCE;

-- Unset masking policy
ALTER TABLE CUSTOMERS MODIFY COLUMN EMAIL UNSET MASKING POLICY;

Projection policy

Sets or unsets a projection policy on the column.

alterProjectionPolicy nested attributes

Attribute	Type	Description	Required
`policyName`	String	Name of the projection policy	No*
`force`	Boolean	If true, forces policy replacement	No
`unsetPolicy`	Boolean	If true, removes the projection policy	No*

*Specify either policyName to set or unsetPolicy to remove.

<?xml version="1.0" encoding="UTF-8"?>
<databaseChangeLog
        xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
        xmlns:pro-snowflake="http://www.liquibase.org/xml/ns/pro-snowflake"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
        http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd
        http://www.liquibase.org/xml/ns/pro-snowflake
        http://www.liquibase.org/xml/ns/pro-snowflake/liquibase-pro-snowflake-latest.xsd">

    <!-- Set projection policy -->
    <changeSet id="set-projection-policy" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="SENSITIVE_DATA" columnName="SECRET_COLUMN">
            <pro-snowflake:alterProjectionPolicy policyName="NO_PROJECTION" force="true"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

    <!-- Unset projection policy -->
    <changeSet id="unset-projection-policy" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="SENSITIVE_DATA" columnName="SECRET_COLUMN">
            <pro-snowflake:alterProjectionPolicy unsetPolicy="true"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

</databaseChangeLog>

databaseChangeLog:
  # Set projection policy
  - changeSet:
      id: set-projection-policy
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: SENSITIVE_DATA
            columnName: SECRET_COLUMN
            alterProjectionPolicy:
              policyName: NO_PROJECTION
              force: true

  # Unset projection policy
  - changeSet:
      id: unset-projection-policy
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: SENSITIVE_DATA
            columnName: SECRET_COLUMN
            alterProjectionPolicy:
              unsetPolicy: true

{
  "databaseChangeLog": [
    {
      "changeSet": {
        "id": "set-projection-policy",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "SENSITIVE_DATA",
              "columnName": "SECRET_COLUMN",
              "alterProjectionPolicy": {
                "policyName": "NO_PROJECTION",
                "force": true
              }
            }
          }
        ]
      }
    },
    {
      "changeSet": {
        "id": "unset-projection-policy",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "SENSITIVE_DATA",
              "columnName": "SECRET_COLUMN",
              "alterProjectionPolicy": {
                "unsetPolicy": true
              }
            }
          }
        ]
      }
    }
  ]
}

-- Set projection policy
ALTER TABLE SENSITIVE_DATA MODIFY COLUMN SECRET_COLUMN SET PROJECTION POLICY NO_PROJECTION FORCE;

-- Unset projection policy
ALTER TABLE SENSITIVE_DATA MODIFY COLUMN SECRET_COLUMN UNSET PROJECTION POLICY;

<?xml version="1.0" encoding="UTF-8"?>
<databaseChangeLog
        xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
        xmlns:pro-snowflake="http://www.liquibase.org/xml/ns/pro-snowflake"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
        http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd
        http://www.liquibase.org/xml/ns/pro-snowflake
        http://www.liquibase.org/xml/ns/pro-snowflake/liquibase-pro-snowflake-latest.xsd">

    <!-- Set projection policy -->
    <changeSet id="set-projection-policy" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="SENSITIVE_DATA" columnName="SECRET_COLUMN">
            <pro-snowflake:alterProjectionPolicy policyName="NO_PROJECTION" force="true"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

    <!-- Unset projection policy -->
    <changeSet id="unset-projection-policy" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="SENSITIVE_DATA" columnName="SECRET_COLUMN">
            <pro-snowflake:alterProjectionPolicy unsetPolicy="true"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

</databaseChangeLog>

databaseChangeLog:
  # Set projection policy
  - changeSet:
      id: set-projection-policy
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: SENSITIVE_DATA
            columnName: SECRET_COLUMN
            alterProjectionPolicy:
              policyName: NO_PROJECTION
              force: true

  # Unset projection policy
  - changeSet:
      id: unset-projection-policy
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: SENSITIVE_DATA
            columnName: SECRET_COLUMN
            alterProjectionPolicy:
              unsetPolicy: true

{
  "databaseChangeLog": [
    {
      "changeSet": {
        "id": "set-projection-policy",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "SENSITIVE_DATA",
              "columnName": "SECRET_COLUMN",
              "alterProjectionPolicy": {
                "policyName": "NO_PROJECTION",
                "force": true
              }
            }
          }
        ]
      }
    },
    {
      "changeSet": {
        "id": "unset-projection-policy",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "SENSITIVE_DATA",
              "columnName": "SECRET_COLUMN",
              "alterProjectionPolicy": {
                "unsetPolicy": true
              }
            }
          }
        ]
      }
    }
  ]
}

-- Set projection policy
ALTER TABLE SENSITIVE_DATA MODIFY COLUMN SECRET_COLUMN SET PROJECTION POLICY NO_PROJECTION FORCE;

-- Unset projection policy
ALTER TABLE SENSITIVE_DATA MODIFY COLUMN SECRET_COLUMN UNSET PROJECTION POLICY;

Comment

Sets or unsets the column comment.

alterColumnComment nested attributes

Attribute	Type	Description	Required
`newComment`	String	New comment text	No*
`unsetComment`	Boolean	If true, removes the comment	No*

*Exactly one of newComment or unsetComment must be specified.

<?xml version="1.0" encoding="UTF-8"?>
<databaseChangeLog
        xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
        xmlns:pro-snowflake="http://www.liquibase.org/xml/ns/pro-snowflake"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
        http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd
        http://www.liquibase.org/xml/ns/pro-snowflake
        http://www.liquibase.org/xml/ns/pro-snowflake/liquibase-pro-snowflake-latest.xsd">

    <!-- Set column comment -->
    <changeSet id="set-column-comment" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="MY_TABLE" columnName="MY_COLUMN">
            <pro-snowflake:alterColumnComment newComment="Customer email address"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

    <!-- Remove column comment -->
    <changeSet id="unset-column-comment" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="MY_TABLE" columnName="MY_COLUMN">
            <pro-snowflake:alterColumnComment unsetComment="true"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

</databaseChangeLog>

databaseChangeLog:
  # Set column comment
  - changeSet:
      id: set-column-comment
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: MY_TABLE
            columnName: MY_COLUMN
            alterColumnComment:
              newComment: "Customer email address"

  # Remove column comment
  - changeSet:
      id: unset-column-comment
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: MY_TABLE
            columnName: MY_COLUMN
            alterColumnComment:
              unsetComment: true

{
  "databaseChangeLog": [
    {
      "changeSet": {
        "id": "set-column-comment",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "MY_TABLE",
              "columnName": "MY_COLUMN",
              "alterColumnComment": {
                "newComment": "Customer email address"
              }
            }
          }
        ]
      }
    },
    {
      "changeSet": {
        "id": "unset-column-comment",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "MY_TABLE",
              "columnName": "MY_COLUMN",
              "alterColumnComment": {
                "unsetComment": true
              }
            }
          }
        ]
      }
    }
  ]
}

-- Set column comment
ALTER TABLE MY_TABLE MODIFY COLUMN MY_COLUMN SET COMMENT 'Customer email address';

-- Remove column comment
ALTER TABLE MY_TABLE MODIFY COLUMN MY_COLUMN UNSET COMMENT;

<?xml version="1.0" encoding="UTF-8"?>
<databaseChangeLog
        xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
        xmlns:pro-snowflake="http://www.liquibase.org/xml/ns/pro-snowflake"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
        http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd
        http://www.liquibase.org/xml/ns/pro-snowflake
        http://www.liquibase.org/xml/ns/pro-snowflake/liquibase-pro-snowflake-latest.xsd">

    <!-- Set column comment -->
    <changeSet id="set-column-comment" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="MY_TABLE" columnName="MY_COLUMN">
            <pro-snowflake:alterColumnComment newComment="Customer email address"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

    <!-- Remove column comment -->
    <changeSet id="unset-column-comment" author="examples">
        <pro-snowflake:alterStandardTableColumn tableName="MY_TABLE" columnName="MY_COLUMN">
            <pro-snowflake:alterColumnComment unsetComment="true"/>
        </pro-snowflake:alterStandardTableColumn>
    </changeSet>

</databaseChangeLog>

databaseChangeLog:
  # Set column comment
  - changeSet:
      id: set-column-comment
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: MY_TABLE
            columnName: MY_COLUMN
            alterColumnComment:
              newComment: "Customer email address"

  # Remove column comment
  - changeSet:
      id: unset-column-comment
      author: examples
      changes:
        - alterStandardTableColumn:
            tableName: MY_TABLE
            columnName: MY_COLUMN
            alterColumnComment:
              unsetComment: true

{
  "databaseChangeLog": [
    {
      "changeSet": {
        "id": "set-column-comment",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "MY_TABLE",
              "columnName": "MY_COLUMN",
              "alterColumnComment": {
                "newComment": "Customer email address"
              }
            }
          }
        ]
      }
    },
    {
      "changeSet": {
        "id": "unset-column-comment",
        "author": "examples",
        "changes": [
          {
            "alterStandardTableColumn": {
              "tableName": "MY_TABLE",
              "columnName": "MY_COLUMN",
              "alterColumnComment": {
                "unsetComment": true
              }
            }
          }
        ]
      }
    }
  ]
}

-- Set column comment
ALTER TABLE MY_TABLE MODIFY COLUMN MY_COLUMN SET COMMENT 'Customer email address';

-- Remove column comment
ALTER TABLE MY_TABLE MODIFY COLUMN MY_COLUMN UNSET COMMENT;

alterStandardTableColumn

Available attributes

Nullable

alterNullable nested attributes

Data type

alterDataType nested attributes

Default value

alterDefault nested attributes

Masking policy

alterMaskingPolicy nested attributes

Projection policy

alterProjectionPolicy nested attributes

Comment

alterColumnComment nested attributes

Tags

alterColumnTags nested attributes

Attribute	Type	Description	Required
`setTags`	Object	Map of tag names to values to set	No*
`unsetTags`	Object	List of tag names to unset	No*

alterStandardTableColumn

Available attributes

Nullable

alterNullable nested attributes

XML

YAML

JSON

SQL

Data type

alterDataType nested attributes

XML

YAML

JSON

SQL

Default value

alterDefault nested attributes

XML

YAML

JSON

SQL

Masking policy

alterMaskingPolicy nested attributes

XML

YAML

JSON

SQL

Projection policy

alterProjectionPolicy nested attributes

XML

YAML

JSON

SQL

Comment

alterColumnComment nested attributes

XML

YAML

JSON

SQL

Tags

alterColumnTags nested attributes