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Displaying posts with tag: signal (reset)

Employee +3 Vote Up -0Vote Down

A new feature just got merged into mysql-trunk, the GET DIAGNOSTICS statement.

Many people have been asking for this for a very long time, so it is worth mentioning it.

mysql> select version();
| version()    |
| 5.6.4-m6-log |
1 row in set (0.00 sec)

mysql> drop table test.no_such_table;
ERROR 1051 (42S02): Unknown table 'test.no_such_table'

Why is it important ? In short, it allows to programmatically (i.e., in SQL) inspect what happened in a SQL exception.

mysql> get diagnostics condition 1
  @p3 = MYSQL_ERRNO,
  @p4 = SCHEMA_NAME,
  @p5 = TABLE_NAME;

Query OK, 0 rows

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Re-implementing udf_init_error in MySQL 5.5 and up
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To whom it may concern -

Today, I received an email from a user of the udf_init_error UDF (which resides in the lib_mysqludf_udf library). The purpose of this UDF is to generate an error condition, which can be used to abruptly terminate a trigger or stored procedure. As such it is a workaround for bug #11661. This is all described extensively in my now ancient article here.

The user wrote me because of a problem experienced in MySQL 5.5:

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Validating MySQL data entry with triggers: A quick look at the SIGNAL syntax
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The latest MySQL 5.5 milestone release offers support for an ANSI/ISO standard feature called the SIGNAL syntax. You can use this syntax inside stored routines (including triggers) to raise an error condition which can be used to invoke specific error handling, or otherwise abort the stored routine. In addition, you can use the SIGNAL syntax to convey information about what went wrong, which may be used by the caller to handle the error.

I have written about MySQL data entry validation procedures in the past. At the time, MySQL did not support any

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Getting started with MySQL 5.5
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Some time go, we announced a new release model for MySQL. As all new things, it had some initial hiccups (with MySQL 5.4 we were still getting acquainted with the new model), but now it seems to be in full swing.
By the time you read these lines, MySQL 5.5 will be available. If the mirrors aren't seeded yet, the impatient can compile and use the new version from the launchpad source tree..


What's this new release anyway? I'll leave it

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Community at work - SIGNAL
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Long time ago, I saw a blog post by Jorge Bernal, with a simple implementation of SIGNAL for MySQL stored procedures. If you have ever tried to write MySQL stored procedures, you know how dearly missed is this feature.
I discussed this feature internally, and everyone told me "don't bother, we're going to implement SIGNAL in MySQL 6.1". And indeed, the full implementation for SIGNAL and RESIGNAL is in the roadmap.

What does that mean? Should we wait two or three more years to

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Showing entries 1 to 5

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