How deeply does Build Python Web Apps with Streamlit cover database update?

Defines UPDATE and works through one conditional text change, but does not develop transaction or concurrency internals.

Database update

As explained in Build Python Web Apps with Streamlit

UPDATE is a SQL statement that changes column values in rows matching an optional condition.

Use UPDATE when an existing database row needs new values. The statement names the table, assigns a column value with SET, and can use WHERE to limit which rows change. section 8.2.4

Updating a haiku

This command adds an attribution prefix to the haiku whose haiku_id is 1: UPDATE haikus SET text = '[By Alice] ' || text WHERE haiku_id = 1;. A following SELECT confirms the changed text.

Treat the condition as an important safety check: it identifies the intended row instead of applying the change broadly. Verify the result with SELECT while developing.

How Build Python Web Apps with Streamlit covers it

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Also explained in

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Learn SQL in a Month of LunchesAn UPDATE statement is an SQL statement that modifies values in existing rows of a table, optionally subject to filtering conditions.
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Spring in Action, Sixth EditionThe JdbcTemplate update method executes a SQL statement that writes or modifies database data and accepts values for its parameters.

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Related concepts

batchingused by · Batching is the grouping of multiple data items, requests, or operations so they can be processed together as a unit.
where clausehas part · A WHERE clause is a query-language clause that restricts returned or affected records to those satisfying a specified predicate.
missing valueuses · A missing value is a marker or condition indicating that an expected data value or reference is absent, unavailable, unknown, or inapplicable.
set clausehas part · A SET clause specifies values or properties to assign or update in a data-manipulation statement.

This explainer was generated by Manning's knowledge graph from the text of Build Python Web Apps with Streamlit. The section links point to the parts of the book it draws on.