将主键和外键添加到 Databricks 上的 SQL 表

Question

I'm new to Databricks and when I want to alter my SQL tables by adding primary or FK, I get an absurd error that can't seem to debug it.

%sql
ALTER TABLE samples_abp215dsdp ADD CONSTRAINT PRIMARY (SampleID);

here is the error message:

Error in SQL statement: ParseException: 
mismatched input '(' expecting {'CHECK', 'FOREIGN', 'PRIMARY', 'UNIQUE'}(line 1, pos 55)

== SQL ==
ALTER TABLE samples_abp215dsdp ADD CONSTRAINT PRIMARY (SampleID)
------------------------------------------------------^^^

any help will be appreciated.

Answer 1

spark do not have any concept of primary key. As spark is computation engine not database.

There are new features coming in 2022 . Follow below list:

• Unity catalog (seems that it will exists next to hive metastore and it will be possible to migrate)
• Control metastore, unity creations etc. from admin console,
• CPU clusters in "create cluster" (similar to SQL endpoints) where you specify how much cpus is needed
• Data lineage
• Delta sharing
• Delta: primary keys
• Delta: foreign keys
• Updated partner connect with many new partners joining
• Notebooks UI: transformations wizards (like select, drop, groupby from droplist etc.)
• New global search
• Integration of job service with git
• Jobs monitoring
• Repair and rerun failed tasks and pass values between tasks
• SQL workflows in SQL view
• create table enhanced via wizard
• Delta live tables in GA
• Serverless DBSQL
• Private links (to VNET and to ExpressRoute) and encryption
• ML: LightGBM, Prophet Models and Text Feature in Auto ML
• ML: Feature store integration with Azure MySQL, Azure SQL and CosmosDB
• ML: Feature store: point in time joins, time-based splits
• ML: Feature store API
• ML: Serverless model serving (enable serving button) with high availability SLA
• ML: one click model deployment into registry

In 2023 :

• Delta: identity column
• Delta: dynamic checkpoints and incremental commits to limit read/write operations with ADLS

Refer this link

Answer 2

Primary Key and Foreign Key are now available on Databricks: https://docs.databricks.com/spark/latest/spark-sql/language-manual/sql-ref-syntax-ddl-create-table-constraint.html