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Diffstat (limited to 'doc/development/polymorphic_associations.md')
| -rw-r--r-- | doc/development/polymorphic_associations.md | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/doc/development/polymorphic_associations.md b/doc/development/polymorphic_associations.md index b71e66c8671..f341255a7e1 100644 --- a/doc/development/polymorphic_associations.md +++ b/doc/development/polymorphic_associations.md @@ -62,19 +62,19 @@ AND source_id = 13083; ``` Here PostgreSQL can perform the query quite efficiently if both columns are -indexed, but as the query gets more complex it may not be able to use these -indexes efficiently. +indexed. As the query gets more complex, it may not be able to use these +indexes effectively. ## Mixed Responsibilities -Similar to functions and classes a table should have a single responsibility: +Similar to functions and classes, a table should have a single responsibility: storing data with a certain set of pre-defined columns. When using polymorphic -associations you are instead storing different types of data (possibly with +associations, you are storing different types of data (possibly with different columns set) in the same table. ## The Solution -Fortunately there is a very simple solution to these problems: use a +Fortunately, there is a solution to these problems: use a separate table for every type you would otherwise store in the same table. Using a separate table allows you to use everything a database may provide to ensure consistency and query data efficiently, without any additional application logic @@ -120,8 +120,8 @@ FROM pending_group_members WHERE group_id = 4 ``` -If you want to get both you can use a UNION, though you need to be explicit -about what columns you want to SELECT as otherwise the result set uses the +If you want to get both you can use a `UNION`, though you need to be explicit +about what columns you want to `SELECT` as otherwise the result set uses the columns of the first query. For example: ```sql |