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4 changes: 4 additions & 0 deletions README.md
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Expand Up @@ -383,3 +383,7 @@ Option 2: on GitHub

1. Edit a file on GitHub.
2. Submit changes as a PR on a new branch.

### Style Guide for EDB contributors

See [EDB documentation style guide](https://enterprisedb.atlassian.net/wiki/spaces/DCBC/pages/2387870239/Documentation+Style+Guide).
38 changes: 19 additions & 19 deletions docs/agreements/doc-release-tag-format.md
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| Product | Key | Tag |
|------------------------------|---------------------------------------------------------|------------------------------------|
| barman | barman | product/barman/*version* |
| Backup and Recovery Tool | bart | product/bart/*version* |
| BDR | bdr | product/bdr/*version* |
| Connectors | *name*-connector, where *name* is jdbc, net, odbc, or ocl | product/*name*-connector/*version* |
| EDB Cloud | edbcloud | product/edbcloud/*version* |
| EDB Postgres Advanced Server | epas | product/epas/*version* |
| Failover Manager | efm | product/efm/*version* |
| Foriegn Data Wrappers | *name*-fdw, where *name* is hadoop, mongo, or mysql | product/*name*-fdw/*version* |
| HARP | harp | product/harp/*version* |
| Migration Portal | mp | product/mp/*version* |
| Migration Toolkit | mtk | product/mtk/*version* |
| Postgres Enterprise Manager | pem | product/pem/*version* |
| pgBackrest | backrest | product/backrest/*version* |
| PgBouncer | pgbouncer | product/pgbouncer/*version* |
| Product | Key | Tag | PM/PO |
|------------------------------|---------------------------------------------------------|------------------------------------| ----- |
| barman | barman | product/barman/*version* | Adam Wright |
| Backup and Recovery Tool | bart | product/bart/*version* | Adam Wright, Robert Haas |
| BDR | bdr | product/bdr/*version* | John Dalton |
| Connectors | *name*-connector, where *name* is jdbc, net, odbc, or ocl | product/*name*-connector/*version* |Eric McCormack (JDBC), Zahid Khan (OCI, ODBC) |
| EDB Cloud | edbcloud | product/edbcloud/*version* | Aislinn Wright |
| EDB Postgres Advanced Server | epas | product/epas/*version* | Robert Haas |
| Failover Manager | efm | product/efm/*version* | John Dalton, Robert Bissett (Bobby) |
| Foriegn Data Wrappers | *name*-fdw, where *name* is hadoop, mongo, or mysql | product/*name*-fdw/*version* | Jeevan Chalke |
| HARP | harp | product/harp/*version* | John Dalton |
| Migration Portal | mp | product/mp/*version* | Prashant Argawal |
| Migration Toolkit | mtk | product/mtk/*version* | Prashant Argawal
| Postgres Enterprise Manager | pem | product/pem/*version* | Anthony Waite, Ashesh Vashi |
| pgBackrest | backrest | product/backrest/*version* | Adam Wright |
| PgBouncer | pgbouncer | product/pgbouncer/*version* | |
| pgPool-II | pgpool | product/pgpool/*version* |
| PostGIS | postgis | product/postgis/*version* |
| PostgreSQL | pgsql | product/pgsql/*version* |
| Replication Manager | repmgr | product/repmgr/*version* |
| Replication Server | eprs | product/eprs/*version* |
| Slony | slony | product/slony/*version* |
| Replication Manager | repmgr | product/repmgr/*version* | John Dalton |
| Replication Server | eprs | product/eprs/*version* | Jphn Dalton |
| Slony | slony | product/slony/*version* | |
61 changes: 31 additions & 30 deletions .../docs/biganimal/release/using_cluster/06_demonstration_oracle_compatibility.mdx
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---
title: "Demonstration of Oracle SQL compatible functions and syntax"
navTitle: "Demo: Oracle SQL compatibility"
navTitle: "Oracle SQL compatibility"
showInteractiveBadge: true
---

BigAnimal lets you run Oracle SQL queries in the cloud via [EDB Postgres Advanced Server](https://www.enterprisedb.com/docs/epas/latest/epas_compat_ora_dev_guide/). This topic demonstrates two Oracle SQL-syntax queries running unmodified on a BigAnimal test cluster, populated with the [Chinook sample database](https://github.com/lerocha/chinook-database).

Watch the video, or load up psql and follow along below!

<figure class="embed-responsive embed-responsive-16by9">
<iframe src="https://www.youtube.com/embed/lV4QQ53kgew"
<iframe src="https://www.youtube.com/embed/lV4QQ53kgew"
title="Video recording of this demonstration"
class="embed-responsive-item"
frameborder="0"
class="embed-responsive-item"
frameborder="0"
allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
</figure>

Expand All @@ -37,20 +38,20 @@ postgres://demo:[email protected]:54
In case you're unfamiliar with [PostgreSQL connection URIs](https://www.postgresql.org/docs/current/libpq-connect.html#id-1.7.3.8.3.6), let's break that down:

- `demo` is the user role we're connecting as. This is a user set up with select privileges on the database.
- `password` is the password for this user.
- `password` is the password for this user.
!!! Warning Passwords in connection strings.
This example illustrates a complete connection URL, including the password. This is fine for a demonstration,
and may also be acceptable for applications configuration if access to the configuration is limited.
and may also be acceptable for applications configuration if access to the configuration is limited.
Avoid this practice for admin, superuser, or other roles used interactively - psql will prompt for a password
if none is supplied.
- `p-c64p9a3h5vfavr7tfrjg.qsbilba3hlgp1vqr.biganimal.io` is the host name for the Advanced Server cluster on BigAnimal that I'm connecting to.
if none is supplied.
- `p-c64p9a3h5vfavr7tfrjg.qsbilba3hlgp1vqr.biganimal.io` is the host name for the Advanced Server cluster on BigAnimal that I'm connecting to.
- `5432` is the usual PostgreSQL port number.
- `chinook` is the name of the database.
- `sslmode=require` ensures that we establish a secure connection.

With that in hand, we can launch psql:

```shell
```shell
psql postgres://demo:[email protected]:5432/chinook?sslmode=require
__OUTPUT__
psql (13.0 (Debian 13.0-1.pgdg100+1), server 13.4.8 (Debian 13.4.8-1+deb10))
Expand Down Expand Up @@ -86,7 +87,7 @@ __OUTPUT__
...
```

There's an employee table, let's examine its definition:
There's an employee table, let's examine its definition:

```
\d+ employee
Expand Down Expand Up @@ -117,17 +118,17 @@ other employees who may in turn report to still *other* employees.

## Demo #1: exposing an organization hierarchy with `CONNECT BY`

Let's construct a [hierarchical query](https://www.enterprisedb.com/docs/epas/latest/epas_compat_ora_dev_guide/03_advanced_concepts/05_hierarchical_queries/) to expose this [chain of command](https://en.wikipedia.org/wiki/Chain_of_command).
Let's construct a [hierarchical query](https://www.enterprisedb.com/docs/epas/latest/epas_compat_ora_dev_guide/03_advanced_concepts/05_hierarchical_queries/) to expose this [chain of command](https://en.wikipedia.org/wiki/Chain_of_command).

Modern SQL would use a recursive CTE for this, as those are widely supported. But Oracle has, for decades, supported an alternative mechanism for querying hierarchy in the form of `CONNECT BY` - let's put that into action:

```sql
SELECT firstname, lastname, (
SELECT LISTAGG(lastname, ', ')
FROM employee rt
START WITH rt.employeeid=e.reportsto
SELECT LISTAGG(lastname, ', ')
FROM employee rt
START WITH rt.employeeid=e.reportsto
CONNECT BY employeeid = PRIOR reportsto
) AS "chain of command"
) AS "chain of command"
FROM employee e;
__OUTPUT__
firstname | lastname | chain of command
Expand All @@ -148,11 +149,11 @@ Now, the `LISTAGG()` function was introduced in Oracle 11g Release 2. Very few d

```sql
SELECT firstname, lastname, (
SELECT string_agg(lastname, ', ')
FROM employee rt
START WITH rt.employeeid=e.reportsto
SELECT string_agg(lastname, ', ')
FROM employee rt
START WITH rt.employeeid=e.reportsto
CONNECT BY employeeid = PRIOR reportsto
) AS "chain of command"
) AS "chain of command"
FROM employee e;
__OUTPUT__
firstname | lastname | chain of command
Expand All @@ -168,20 +169,20 @@ __OUTPUT__
(8 rows)
```

But [the semantics of the two functions are different for even slightly less-trivial uses](https://www.enterprisedb.com/blog/how-workaround-oracle-listagg-function-postgresql), specifically when using the grouping construct.
But [the semantics of the two functions are different for even slightly less-trivial uses](https://www.enterprisedb.com/blog/how-workaround-oracle-listagg-function-postgresql), specifically when using the grouping construct.

Let's demonstrate that.
Let's demonstrate that.

## Demo #2: group concatenation with `LISTAGG`

As we saw above, this database has "album" and "track" tables containing metadata on digital recordings. We can use some analytic functions, including `LISTAGG`, to put together a report on average track storage requirements for albums with "baby" in the title.

```sql
SELECT UNIQUE title,
SELECT UNIQUE title,
ROUND(AVG(bytes) OVER (PARTITION BY mediatypeid)/1048576 ) media_avg_mb,
LISTAGG(t.name || ' (' || ROUND(bytes/1048576) || ' mb)', chr(10))
LISTAGG(t.name || ' (' || ROUND(bytes/1048576) || ' mb)', chr(10))
WITHIN GROUP (ORDER BY trackid)
OVER (PARTITION BY title) track_list
OVER (PARTITION BY title) track_list
FROM track t
JOIN album USING (albumid)
JOIN mediatype USING (mediatypeid)
Expand All @@ -208,11 +209,11 @@ __OUTPUT__
If we try replacing `LISTAGG` with `string_agg` in this example, it's going to fail - the [expression syntax for `string_agg`](https://www.postgresql.org/docs/current/sql-expressions.html#SYNTAX-AGGREGATES) is different.

```sql
SELECT UNIQUE title,
SELECT UNIQUE title,
ROUND(AVG(bytes) OVER (PARTITION BY mediatypeid)/1048576 ) media_avg_mb,
string_agg(t.name || ' (' || ROUND(bytes/1048576) || ' mb)', chr(10))
string_agg(t.name || ' (' || ROUND(bytes/1048576) || ' mb)', chr(10))
WITHIN GROUP (ORDER BY trackid)
OVER (PARTITION BY title) track_list
OVER (PARTITION BY title) track_list
FROM track t
JOIN album USING (albumid)
JOIN mediatype USING (mediatypeid)
Expand All @@ -225,13 +226,13 @@ LINE 3: string_agg(t.name || ' (' || ROUND(bytes/1048576) || ...
HINT: No function matches the given name and argument types. You might need to add explicit type casts.
```

Now, this isn't terribly difficult to correct, but it requires restructuring the query to replace the grouping construct - such work can quickly accumulate errors. Fortunately, [EDB Postgres Advanced Server](https://www.enterprisedb.com/docs/epas/latest/)
supports [`LISTAGG`](https://www.enterprisedb.com/docs/epas/latest/epas_compat_reference/02_the_sql_language/03_functions_and_operators/11_aggregate_functions/#listagg) AND `string_agg`,
Now, this isn't terribly difficult to correct, but it requires restructuring the query to replace the grouping construct - such work can quickly accumulate errors. Fortunately, [EDB Postgres Advanced Server](https://www.enterprisedb.com/docs/epas/latest/)
supports [`LISTAGG`](https://www.enterprisedb.com/docs/epas/latest/epas_compat_reference/02_the_sql_language/03_functions_and_operators/11_aggregate_functions/#listagg) AND `string_agg`,
so this query doesn't need to change when migrating from Oracle.

## Compatibility preserves the value of your existing work

In both of the examples shown here, you probably would not use the functions and syntax demonstrated for new work; there are
In both of the examples shown here, you probably would not use the functions and syntax demonstrated for new work; there are
better, more familiar or at least more widely-available equivalents provided natively by PostgreSQL (and many other databases). But by supporting them, EDB Advanced Server gives you the ability to reuse existing logic with minimal modification, allowing
you to focus your time and expertise on solving new problems.

Expand Down
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