liquibase-snowflake
Liquibase extension to add Snowflake support
Snowflake Extension
Initial release supports applying formatted sql changesets. It might support other types of refactorings but they haven't been tested. Some of the interesting overrides / extensions are documented below.
Database
currentDateTimeFunction
Snowflake's current_timestamp
function returns a timestamp_ltz
datetype, while
the datetime
Liquibase datatype maps to a Snowflake timestamp_ntz
column. To avoid exceptions, the current_timestamp
is cast to a timestamp_ntz
. Without the cast, exceptions of the form given below occur.
SQL compilation error: Expression type does not match column data type, expecting TIMESTAMP_NTZ(9) but got TIMESTAMP_LTZ(9)
getJdbcCatalogName
The Snowflake JDBC drivers implementation of DatabaseMetadata.getTables()
hard codes quotes around the catalog, schema and
table names, resulting in queries of the form:
show tables like 'DATABASECHANGELOG' in schema "sample_db"."sample_schema"
This results in the DATABASECHANGELOG
table not being found, even after it has been created. Since Snowflake stores
catalog and schema names in upper case, the getJdbcCatalogName returns an upper case value.
getJdbcSchemaName
Datatype Mappings
datetime
The datetime
datatype in Snowflake is an alias for the datatype timestamp_ntz
, Date and Time Data Types.
The TimestampNTZType
class clarifies this mapping from Liquibase datetime
to Snowflake timestamp_ntz
.