Alter Standard Table - Column

alterStandardTableColumn

Last updated: February 13, 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;