Snowflake Connection
You can connect to Snowflake in the same way as to any other SQL database using a DB Connection with the bundled Snowflake JDBC driver.
This section contains information about working with date-time data types that is common to DatabaseReader, DatabaseWriter and SnowflakeBulkWriter.
Date/Time Data Types in Snowflake
Working with dates and time zones can be challenging. As a quick rule before going into details, always specify the Format of date data fields in your metadata, see Date and Time Format. Also setting the Session Time Zone on the connection to match your local time zone may help.
There are five different Snowflake data types and two time zones (session TZ and local TZ) that affect the results.
| Snowflake type | Description | Time zone |
|---|---|---|
DATE |
A date without a time component. |
local |
TIME |
Wallclock time without a date. |
|
TIMESTAMP_NTZ |
Date and time without a time zone. Saved as the wallclock date-time in the session time zone. The time zone itself is not stored. |
session |
TIMESTAMP_TZ |
Date and time with a time zone. The session time zone is stored as a part of the value and used for reading. |
|
TIMESTAMP_LTZ |
Written in the local time zone, but the time zone is not stored. The current time zone is always used for reading. |
local |
All of these Snowflake types map to just one data type in CloverDX metadata: date.
An important property of the date data type is its Format. It provides a hint on how to interpret the data while reading or writing them to the database.
If the Format contains only a date part, it maps to the DATE type. If it contains only a time part, we consider it a TIME. And if it contains both, we treat it as a TIMESTAMP.
For example, "yyyy-MM-dd" or "dd/MM/yyyy" are DATE formats, "HH:mm:ss" is a TIME format, and "dd.MM.yyyy HH:mm:ss" is a TIMESTAMP.
See Date and Time Format for more details.
Note that regardless of the Format, CloverDX records store the full date and time value. The Format controls how that value is interpreted when reading and writing data.
Session Time Zone
This is the time zone of the connection, as configured in Snowflake. It is used for writing TIMESTAMPs.
See the TIMEZONE parameter in Snowflake documentation.
You can override the session time zone on the connection in Advanced Properties of JDBC driver, e.g., TIMEZONE=Asia/Singapore.
Local Time Zone
This is the client time zone. It is used for reading and writing DATE and TIME columns. It is set to your system time zone by default. But you can override it in your metadata, even for individual fields. See Date and Time Format and Time Zone for details.
Using Snowflake in Server Core
If you want to use Snowflake connection in a graph that runs in Server Core, the server needs to be configured to allow reflective access. See reflective access.