Redshift alter table remove constraint how to#
Redshift alter table remove constraint full#

The columns in a table are called fields while the rows can be referred to as records. Columns can be categorized as vertical and rows as horizontal. Differentiate between commit and checkpoint.Ī table is an organized collection of data stored in the form of rows and columns.

Redshift alter table remove constraint full#

Does PostgreSQL support full text search? How will you take backup of the database in PostgreSQL? How do you perform case-insensitive searches using regular expressions in PostgreSQL? What is the main disadvantage of deleting data from an existing table using the DROP TABLE command? What can you tell about WAL (Write Ahead Logging)? How do you check the rows affected as part of previous transactions? What do you understand by command enable-debug? What do you understand by multi-version concurrency control? Can you explain the architecture of PostgreSQL? What are ACID properties? Is PostgreSQL compliant with ACID? How can you delete a database in PostgreSQL? How can you get a list of all databases in PostgreSQL? What is the capacity of a table in PostgreSQL? What is the importance of the TRUNCATE statement?

What are partitioned tables called in PostgreSQL? How can we start, restart and stop the PostgreSQL server? What is the command used for creating a database in PostgreSQL? How will you change the datatype of a column?

Redshift alter table remove constraint how to#

How to create empty tables with the same structure as another table? What is Collation? What are the different types of Collation Sensitivity? What are the differences between OLTP and OLAP? What is User-defined function? What are its various types? What is the difference between DELETE and TRUNCATE statements? What is the difference between DROP and TRUNCATE statements? What are the TRUNCATE, DELETE and DROP statements? What are the various forms of Normalization? List the different types of relationships in SQL. What are UNION, MINUS and INTERSECT commands? What are some common clauses used with SELECT query in SQL? What is the difference between Clustered and Non-clustered index? What is an Index? Explain its different types. What is a Join? List its different types. What is the difference between SQL and MySQL? What is RDBMS? How is it different from DBMS? Since what I talked about is mostly about documenting the relationship between models, I think the sensible place for it to be would be in the YAML files, and then we should have an option some how to generate the “alter table” statements to make those Question to you: do we have access to the data in the YAML files when executing post-hooks? I thinking it would be relatively easy to create a macro that you invoke from a post-hook to parse the list of columns and generate those exact “alter table” statements. Someone wanting to take advantage of that would have to use post hooks to successfully implement that. If you have that information in place, when you use Metabase query builder, it’s able to show to the end user the fields of the joined table so they can be filtered upon. Metabase automatically fills in Table metadata for you if foreign and primary keys information is available, it fills out metadata about the tables.

When you query data, you can use the context menu to select data that match a foreign key column from a query result, for example. These Database clients use the Primary Key and Foreign Key information to auto complete join conditions when writing SQL queries. Navigating related data and auto-completing SQL queries become a lot better, in DataGrip at least. Two main use cases on the top of my mind:

I didn’t see anyone mention it here, but the main case for primary/foreign key constraints in data warehouses is data discoverability.

Where would I define the PK/FK constraints within the model? Have not seen documentation about this, possibly missed that part.ĭescription: A table containing all customersĭescription: This is a unique identifier in the customerĭescription: This is a unique identifier in the supplier table.

What does the dbt-tool actually check for in the case of ‘relationships’?.

However, for those tables in the data warehouse i’m developing as of now, there are no PK/FK constraints - I have defined that in postgres myself or figured out where to define that within the models schema. I’ve set relationships between tables and when I run the test command those tests are successful (i.e PASS). With what i’ve read and tested so-far I was under the false impression of what the ‘relationships’ method of the testing feature does.