UpdateMultiple · PostgreSQL in C#

What an UpdateMultiple does


Many rows	Rows with the same attributes go in one statement (`UPDATE … FROM unnest(…)`, one array per column), wherever they are in the list
Without a catalog	The table is read once for the whole list, then every row is changed, all or nothing (Basic2)
By a filter	One entity with the values to set and an `ArxFilterExpression`: one `UPDATE … SET … WHERE …` for every row the filter matches, returning the count (Basic3). The entity carries no id (ARX1001); an empty filter needs `AllRows`; a version column goes up by one on each changed row. From 0.1.0-preview.5

The samples

Basics

The least code that works.

1Update many records in one callStandalone

Many records in one call, in three scenarios: a different value for each row, rows that change different attributes, and all or nothing when one record doesn't exist.

2Update many records without a catalogStandalone

Many records in one call on a service created with only a connection string: the account table is read from the database once for the whole list, then every row is changed, all or nothing.

3Update every row a filter matchesStandalone

Every row a condition matches, changed in one call: the entity carries only the values to set, and a filter says which rows. The call returns how many rows it changed.

Real cases

What an application does: a small CRM and product catalogue.

1Put accounts on hold (selection set, by key)Progressive

Credit control puts accounts on hold, in three scenarios: one account by its account number (the declared key); a value the status picklist doesn't allow is refused before the database; every account of a segment at once.

2Reprice 20,000 products from a feedProgressive

A supplier's price feed reprices the catalogue, in two scenarios: 20,000 products by SKU in one call (one set-based statement), and a feed with a SKU the catalogue doesn't have, which changes nothing.

Advanced cases

Dependency injection, transactions, batch scopes and setting the service up.

1Stock counts in batches: one transaction, a failed batch skippedAdvanced

A stock count file updates products in batches, in two scenarios: every batch in one transaction with automatic commit; and a batch that fails, skipped while the others are kept (savepoints, manual commit).