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https://issues.apache.org/jira/browse/PHOENIX-476?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15497128#comment-15497128
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Kevin Liew edited comment on PHOENIX-476 at 9/16/16 7:15 PM:
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If we consider the following case:

{noformat}
create table testdefault (pk integer primary key, test integer default 5);

upsert into testdefault values (1, null);

select * from testdefault;
{noformat}

We expect `1, <null>` but if we use `COALESCE` while retrieving the second 
column, would we get `1, 5`? 

I suppose CoalesceFunction will differentiate between null parse nodes and null 
values and that would give us the expected result?


was (Author: kliew):
If we consider the following case:

{noformat}
create table testdefault (pk integer primary key, test integer default 5);

upsert into testdefault values (1, null);

select * from testdefault;
{noformat}

We expect `1, <null>` but if we use `COALESCE` while retrieving the second 
column, would we get `1, 5`? 

I suppose CoalesceFunction will differentiate between null parse nodes and null 
values.

> Support declaration of DEFAULT in CREATE statement
> --------------------------------------------------
>
>                 Key: PHOENIX-476
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-476
>             Project: Phoenix
>          Issue Type: Task
>    Affects Versions: 3.0-Release
>            Reporter: James Taylor
>            Assignee: Kevin Liew
>              Labels: enhancement
>         Attachments: PHOENIX-476.2.patch, PHOENIX-476.patch
>
>
> Support the declaration of a default value in the CREATE TABLE/VIEW statement 
> like this:
>     CREATE TABLE Persons (
>         Pid int NOT NULL PRIMARY KEY,
>         LastName varchar(255) NOT NULL,
>         FirstName varchar(255),
>         Address varchar(255),
>         City varchar(255) DEFAULT 'Sandnes'
>     )
> To implement this, we'd need to:
> 1. add a new DEFAULT_VALUE key value column in SYSTEM.TABLE and pass through 
> the value when the table is created (in MetaDataClient).
> 2. always set NULLABLE to ResultSetMetaData.columnNoNulls if a default value 
> is present, since the column will never be null.
> 3. add a getDefaultValue() accessor in PColumn
> 4.  for a row key column, during UPSERT use the default value if no value was 
> specified for that column. This could be done in the PTableImpl.newKey method.
> 5.  for a key value column with a default value, we can get away without 
> incurring any storage cost. Although a little bit of extra effort than if we 
> persisted the default value on an UPSERT for key value columns, this approach 
> has the benefit of not incurring any storage cost for a default value.
>     * serialize any default value into KeyValueColumnExpression
>     * in the evaluate method of KeyValueColumnExpression, conditionally use 
> the default value if the column value is not present. If doing partial 
> evaluation, you should not yet return the default value, as we may not have 
> encountered the the KeyValue for the column yet (since a filter evaluates 
> each time it sees each KeyValue, and there may be more than one KeyValue 
> referenced in the expression). Partial evaluation is determined by calling 
> Tuple.isImmutable(), where false means it is NOT doing partial evaluation, 
> while true means it is.
>     * modify EvaluateOnCompletionVisitor by adding a visitor method for 
> RowKeyColumnExpression and KeyValueColumnExpression to set 
> evaluateOnCompletion to true if they have a default value specified. This 
> will cause filter evaluation to execute one final time after all KeyValues 
> for a row have been seen, since it's at this time we know we should use the 
> default value.



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