How Can I Update Multiple Tables Simultaneously in SQL Server 2005?

SQL Server 2005: Simultaneous Multi-Table Updates

Updating multiple tables concurrently is a common database task. SQL Server 2005, however, presents unique challenges in this regard. This article outlines effective strategies for achieving this.

Methods for Multi-Table Updates

Unlike some newer database systems, SQL Server 2005 doesn't directly support updating multiple tables with a single UPDATE statement. Instead, we rely on transactions or clever use of table aliasing.

Transaction-Based Approach

Transactions provide an atomic unit of work. Multiple UPDATE statements are grouped within a transaction; either all succeed, or none do, maintaining data consistency. Here's an illustrative example:

<code class="language-sql">BEGIN TRANSACTION;

UPDATE Table1
SET LastName = 'DR. XXXXXX'
WHERE id = '011008';

UPDATE Table2
SET WAprrs = 'start,stop'
WHERE id = '011008';

COMMIT;</code>

This example uses a transaction to ensure that both UPDATE statements either complete successfully or are completely reversed if an error occurs.

Batched Updates with Table Aliasing

Table aliasing offers an alternative. By creating an updatable alias, we can combine UPDATE statements, reducing database round trips. However, note that this method lacks the atomicity guaranteed by transactions.

<code class="language-sql">UPDATE
  (SELECT * FROM Table1 T1 JOIN Table2 T2 ON T1.id = T2.id) AS UpdatableAlias
SET
  LastName = 'DR. XXXXXX',
  WAprrs = 'start,stop'
WHERE
  id = '011008';</code>

This approach joins Table1 and Table2 into the UpdatableAlias, then applies the updates using this combined view. While efficient, remember that a failure in one part of the update might affect the other. Transactions provide a more robust solution for critical data integrity.

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