Hi,
Ø I don't love the idea of an annotation being
an acronym.
That’s not completely
uncommon, e.g. @EJB.
-Adrian
James,
Interesting. Some feedback on this proposal:
- I like the idea of being able
to specify the full create table string similar to how
@Column allows you to specify a replacement
columnDefinition.
- I don't love the idea of an
annotation being an acronym. I would prefer to see an
annotation that is more readable as to what it will do.
- If you can provide a create
string or suffix for one or more database platforms then you
should be able to specify multiples
- I prefer the platform names
used in TARGET_DATABASE ("eclipselink.target-database")
property and believe we should take strings and process them
in a similar fashion using the string as a class name if a
short name match is not found
- Unsure what exactly you mean by
override. If the full sql is provided it is used as is. If a
suffix is provided it is used in conjunction with the
generated sql. If no value is provided for the current
platform then the default generated sql is used.
- Should we include specifying
the DROP TABLE syntax for specific platforms as well so I
could get the CASCADE CONSTRAINTS included on platforms that
support it.
As a rough idea we could support something like:
@Entity
@Table(name="BLAH")
@DDL(
create={
@CreatTable(suffix="engine=InnoDB" platforms="MySQL"),
@CreateTable(sql="CREATE TABLE blah ... tablespace
X, initial size 512m" platforms="Oracle")
}
drop=@DropTable(sql="DROP TABLE blah CASCADE CONSTRAINTS",
platforms={"Oracle"})
)
public class Blah {
...
On 04/04/2011 8:39 AM, James Sutherland wrote:
I don't think we should be using
descriptor properties for this (or any) feature.
If we have a specific feature, we
should have a specific annotation for it.
I would propose,
@DDL(ddl, table, suffix,
override, databases)
.i.e
@DDL(suffix="engine=InnoDB",
databases=MySQLPlatform.class)
@DDL(ddl="create hash index
empname_inx on employee by name")
@DDL(ddl="create table employee
(id numeric(20), name varchar2(512)) tablespace amce3,
initial size 512m, overrude=true,
databases=OraclePlatform.class)
I don't think we should add infix
or prefix unless we have valid examples of these. I do
not know of any, other than "temporary" which is not
relevant.
Please give concrete examples for
this feature.
-----Original
Message-----
From: douglas clarke
Sent: Friday, April 01, 2011 2:43 PM
To: eclipselink-dev@xxxxxxxxxxx
Subject: Re: [eclipselink-dev] bug 340329 - table
creation prefix
The original
issue that lead to the suffix capability was very specific to
the engine=InnoDB usage.
I believe what we are now discussing is a slightly broader set
of requirements around augmenting the CREATE TABLE DDL
statement.
I would say the requirements are now:
Allow a developer to specify a suffix
for the CREATE DATABASE at the PU level or specifically on a
given entity's table(s)
Allow a developer to specify a prefix for
the CREATE DATABASE at the PU level or specifically on a given
entity's table(s)
Allow the developer to specify the platform a suffix
or prefix applies to and only use it in that case
One approach
would be to deprecate the <table suffix support and extend
the existing properties support to apply to entities and to
allow the property to be specified as platform specific.
PU property (already exists):
"eclipselink.ddl-generation.table-creation-suffix" - indicates
a suffix used on all CREATE TABLES for all platforms
Add platform support:
"eclipselink.ddl-generation.table-creation-suffix.MySQL" -
indicates a suffix for all CREATE TABLES issued against a
database platform with the short name 'MySQL'.
Then we could extend this support on a per-entity basis using
EclipseLink's properties for cases where a developer needs to
supply these values differently for different entity table(s).
@Entity
@Properties({
@Property(name="eclipselink.ddl-generation.table-creation-suffix.MySQL",
value="engine=InnoDB"),
@Property(name="eclipselink.ddl-generation.table-creation-prefix.MaxDB",
value="???")
})
public class Foo {
This of course could also be specified in the
eclispelink-orm.xml within an entities's properties tags.
Doug
On 29/03/2011 8:29 AM, Tom Ware wrote:
That's a reasonable point. In
the end, I guess it comes down to a choice about which is more
important to us, the flexibility or the portability.
My vote is for the flexibility due to the fact that we
currently only know of one suffix and it is not even necessary
if you set your MySQL to use Innodb. DDL Generation, after
all, is only a development-time feature.
I wonder if James' suggesting of a larger DDL config could be
used to address this problem more generally. I guess it
depends on if we want to worry about that larger feature now,
or if it is more important to get the prefix work.
Other committers... What do you think?
-Tom
Goerler, Adrian wrote:
Hi,
We thought about the
delegation model you suggest below. The weakness is, of
course, that it requires a code change to deal with any
property that might be passed in. (i.e. if MySQL added a new
modifier other than INNODB, we'd have to actually change the
MySQLPlatform to support it). So far, the features that are
addressed with the suffix are fairly obscure, so we thought it
would be better to leave it free form. I am, however open to
arguments the other way.
an advantage of the delegation model would be that properties
(or hints) not applicable for the current database platform
would just be ignored. With the free from suffix, I can't run
the same application on two different database platforms.
-Adrian
Adrian Görler
SAP AG
Pflichtangaben/Mandatory Disclosure Statements:
http://www.sap.com/company/legal/impressum.epx
-----Original Message-----
From: eclipselink-dev-bounces@xxxxxxxxxxx
[mailto:eclipselink-dev-bounces@xxxxxxxxxxx]
On Behalf Of Tom Ware
Sent: Montag, 28. März 2011 19:29
To: Dev mailing list for Eclipse Persistence Services
Cc: Singer, Reiner
Subject: Re: [eclipselink-dev] bug 340329 - table creation
prefix
Hi Adrian,
I'd like to hear what other committers think but I think my
preference is to specify this as a "table creation modifier"
or some such thing. (your infix suggestion)
Unless we can think of a case where we would not have both
the "CREATE" and "TABLE" strings, I think it would be cleaner
to avoid requiring they be specified.
We thought about the delegation model you suggest below.
The weakness is, of course, that it requires a code change to
deal with any property that might be passed in. (i.e. if
MySQL added a new modifier other than INNODB, we'd have to
actually change the MySQLPlatform to support it). So far, the
features that are addressed with the suffix are fairly
obscure, so we thought it would be better to leave it free
form. I am, however open to arguments the other way.
-Tom
Goerler, Adrian wrote:
Hi Tom,
yes, a "prefix" as propsed in the patch would substitute
"CREATE TABLE". I agree that "prefix" does not appear to be
the right terminology. "createTableStatement" isn't either as
its only the first part of the statement. Maybe
"createTableKeywords" would be better or
"createTableStatementHeader".
It is an SAP-specific future feature we would like leverage,
which allows to control some storage parameters of a table.
The actual Syntax has the structure "CREATE <modifier>
TABLE". Hence specifying the <modifier> as an "infix"
would also be OK.
Still, I am afraid that this (prefix/suffix) opens a small can
of worms and it might be cleaner to delegate writeCreateTable
to the platform as scetched out below.
-Adrian
Adrian Görler
SAP AG
Pflichtangaben/Mandatory Disclosure Statements:
http://www.sap.com/company/legal/impressum.epx
-----Original Message-----
From: eclipselink-dev-bounces@xxxxxxxxxxx
[mailto:eclipselink-dev-bounces@xxxxxxxxxxx]
On Behalf Of Tom Ware
Sent: Montag, 28. März 2011 16:55
To: Dev mailing list for Eclipse Persistence Services
Cc: Xiang, Xu; Singer, Reiner
Subject: Re: [eclipselink-dev] bug 340329 - table creation
prefix
What would a typical prefix be? (is it really a prefix, or a
replacement for "CREATE TABLE"? Is PREFIX the right
terminology?)
When would someone choose to use a prefix? Is this a MAXDB
specific thing?
-Tom
Goerler, Adrian wrote:
Hi Chris, others,
https://bugs.eclipse.org/bugs/show_bug.cgi?id=340329
we got the requirement to allow overriding the CREATE TABLE
keywords in DDL in a table-specific way to leverage special
database features. Xu has proposed to introduce a
creation-prefix attribute to the table-mappings of
eclipselink-orm.xml - analogously to https://bugs.eclipse.org/bugs/show_bug.cgi?id=214519.
Please find attached a revised proposal including test for
this enhancement.
I you are OK with this feature, I would go ahead and check it
in.
-Adrian
PS.
Alternatively, I could consider to specify additional
requirements on the DDL using @Properties/@Property
annotations. Then, one could add hese properties to the
TableDefinition, redirect rendering of CREATE TABLE statements
to the DatabasePlatform and render the statement in a
database-vendor specific way according to the properties
recognized by the vendor.
E.g.:
@Table(name="MY_TABLE")
@Property("mysql.jdbc.engine", "InnoDB")
@Entity
Public class MyEntity
This, however, would obsolete the creation-suffix just
introduced in 2.2 ;-).
*Adrian Görler
**SAP AG
*Pflichtangaben/Mandatory Disclosure Statements:
http://www.sap.com/company/legal/impressum.epx
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