When you enter a TQL statement, the system warns you of possible dependency consequences with a prompt asking if you’d like to proceed. This should make you feel safe issuing TQL commands, even commands like dropping a table.
TQL actions with possible dependency consequences include:
- Change, add, or remove a primary key.
- When changing or adding a primary key, if the key in question is not unique in the data it may cause deletion of rows, because of upserts occurring when duplicate primary keys are found.
- When changing or removing a primary key, incoming foreign key relationships will be broken.
- Change a column datatype.
- Add a relationship or foreign key.
- Drop a relationship or foreign key constraint.
- Change or add a sharding key.
- Drop a table, schema, or database.
When issuing one of the previous commands, you will see a warning message similar to this:
TQL> ALTER TABLE table1 DROP CONSTRAINT PRIMARY KEY; WARNING: This operation will break the Foreign Key relationship “products” with table “sales”, which will break 34 user-visible visualizations and 2 Worksheets. We recommend taking a snapshot before performing this operation. Do you wish to proceed? (yes/no).