Glossary
Every term the courses use, defined in one line and then in a paragraph. Written to be read out of order.
Showing 6 of 6 matching “Schema”
Filling in historical data after adding a new column.
The step in a safe schema change where existing rows are given values for a newly added column. Usually done in batches so it does not lock the table or overwhelm the database.
A recorded, ordered change to your data’s shape.
A versioned schema change applied identically in every environment. Needed because code can be rolled back in seconds and data cannot. Safe changes expand first, then contract days later.
Databases that are not table-and-row relational.
A loose family including document, key-value and graph stores. Flexible shape and easier extreme scale, at the cost that nothing prevents two records disagreeing about structure. The schema does not disappear; it moves into your code.
See also SQL, Document store, Schema
The declared shape of your data.
Which tables exist, which columns they have, and what is allowed in them. Changing it is a migration. In schemaless databases the schema still exists, just in your code instead of the database.
Checking that input is what you expected.
In the browser it is a courtesy that makes things pleasant. On the server it is a control, because requests do not have to come from your form. You need both, ideally from one shared schema so they cannot disagree.
See also Server function, Search params, Client
Running old and new API shapes side by side.
Offering /v1 and /v2 so existing callers keep working while new ones use the new shape. The same expand-then-contract idea as a safe schema migration, applied to an API.
See also Breaking change, Deprecation