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Diffstat (limited to 'docs/topics/db/sql.txt')
| -rw-r--r-- | docs/topics/db/sql.txt | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/docs/topics/db/sql.txt b/docs/topics/db/sql.txt index 80038e547f..d387ad5520 100644 --- a/docs/topics/db/sql.txt +++ b/docs/topics/db/sql.txt @@ -69,6 +69,16 @@ options that make it very powerful. database, but does nothing to enforce that. If the query does not return rows, a (possibly cryptic) error will result. +.. warning:: + + If you are performing queries on MySQL, note that MySQL's silent type coercion + may cause unexpected results when mixing types. If you query on a string + type column, but with an integer value, MySQL will coerce the types of all values + in the table to an integer before performing the comparison. For example, if your + table contains the values ``'abc'``, ``'def'`` and you query for ``WHERE mycolumn=0``, + both rows will match. To prevent this, perform the correct typecasting + before using the value in a query. + Mapping query fields to model fields ------------------------------------ |