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docs/ComputedRecords.md

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+_Overview of Computed Records._
+
+Note: computed records are largely deprecated in favor of ad-hoc queries or the use of
+`selectInto`. See [the example queries page](ExampleQueries) for examples of such use.
+
+## Computed Records
+
+You can easily define record with computed fields or records that represent a join across multiple
+tables (see below). It is very easy to select a subset of a record's fields:
+
+```java
+@Entity @Computed(shadowOf=PersonRecord.class)
+public PersonNameRecord extends PersistentRecord
+{
+    public int personId;
+    public String name;
+}
+
+List<PersonNameRecord> allNames = findAll(PersonNameRecord.class);
+List<PersonNameRecord> youngNames = findAll(
+    PersonNameRecord.class, new Where(PersistentRecord.AGE.lessEq(18)));
+```
+
+You can also define computed records that calculate information:
+
+```java
+@Entity @Computed
+public CountRecord extends PersistentRecord
+{
+    @Computed(fieldDefinition="count(*)")
+    public int count;
+}
+
+int personCount = load(CountRecord.class, new FromOverride(PersonRecord.class)).count;
+
+// or if you want to be less general purpose
+
+@Entity @Computed(shadowOf=PersonRecord.class)
+public PersonCountRecord extends PersistentRecord
+{
+    @Computed(fieldDefinition="count(*)")
+    public int count;
+}
+
+int personCount = load(PersonCountRecord.class).count;
+
+// or something more specific
+
+@Entity @Computed(shadowOf=PersonRecord.class)
+public PersonAvgAgeRecord extends PersistentRecord
+{
+    @Computed(fieldDefinition="avg(*)")
+    public float averageAge;
+}
+
+float averageAge = load(PersonAvgAgeRecord.class).averageAge;
+```
+
+The reader may be alarmed to notice some hard-coded SQL in those classes. One is advised to stick
+to very standard SQL in cases like this to avoid introducing portability problems, but we didn't
+think it was worth the trouble to try to model these simple and mostly standard operations in a
+more complex way. YMMV.
+
+## Joins with Computed Records
+
+TBD