Oren Eini

aka Ayende Rahien

Oren Eini

CEO of RavenDB

a NoSQL Open Source Document Database

Get in touch with me:

oren@ravendb.net

+972 52-548-6969

Posts: 7,546

|

Comments: 51,163

Copyright ©️ Ayende Rahien 2004 — 2025

Privacy Policy · Terms

filter by tags archive

architecture (599) rss
bugs (447) rss
challanges (123) rss
community (372) rss
databases (480) rss
design (892) rss
development (628) rss
hibernating-practices (69) rss
miscellaneous (592) rss
performance (390) rss
programming (1074) rss
raven (1420) rss
ravendb.net (501) rss
reviews (184) rss

2024
- December (3)
- November (2)
- October (1)
- September (3)
- August (5)
- July (10)
- June (4)
- May (6)
- April (2)
- March (8)
- February (2)
- January (14)
2023
- December (4)
- October (4)
- September (6)
- August (12)
- July (5)
- June (15)
- May (3)
- April (11)
- March (5)
- February (5)
- January (8)
2022
- December (5)
- November (7)
- October (7)
- September (9)
- August (10)
- July (15)
- June (12)
- May (9)
- April (14)
- March (15)
- February (13)
- January (16)
2021
- December (23)
- November (20)
- October (16)
- September (6)
- August (16)
- July (11)
- June (16)
- May (4)
- April (10)
- March (11)
- February (15)
- January (14)
2020
- December (10)
- November (13)
- October (15)
- September (6)
- August (9)
- July (9)
- June (17)
- May (15)
- April (14)
- March (21)
- February (16)
- January (13)
2019
- December (17)
- November (14)
- October (16)
- September (10)
- August (8)
- July (16)
- June (11)
- May (13)
- April (18)
- March (12)
- February (19)
- January (23)
2018
- December (15)
- November (14)
- October (19)
- September (18)
- August (23)
- July (20)
- June (20)
- May (23)
- April (15)
- March (23)
- February (19)
- January (23)
2017
- December (21)
- November (24)
- October (22)
- September (21)
- August (23)
- July (21)
- June (24)
- May (21)
- April (21)
- March (23)
- February (20)
- January (23)
2016
- December (17)
- November (18)
- October (22)
- September (18)
- August (23)
- July (22)
- June (17)
- May (24)
- April (16)
- March (16)
- February (21)
- January (21)
2015
- December (5)
- November (10)
- October (9)
- September (17)
- August (20)
- July (17)
- June (4)
- May (12)
- April (9)
- March (8)
- February (25)
- January (17)
2014
- December (22)
- November (19)
- October (21)
- September (37)
- August (24)
- July (23)
- June (13)
- May (19)
- April (24)
- March (23)
- February (21)
- January (24)
2013
- December (23)
- November (29)
- October (27)
- September (26)
- August (24)
- July (24)
- June (23)
- May (25)
- April (26)
- March (24)
- February (24)
- January (21)
2012
- December (19)
- November (22)
- October (27)
- September (24)
- August (30)
- July (23)
- June (25)
- May (23)
- April (25)
- March (25)
- February (28)
- January (24)
2011
- December (17)
- November (14)
- October (24)
- September (28)
- August (27)
- July (30)
- June (19)
- May (16)
- April (30)
- March (23)
- February (11)
- January (26)
2010
- December (29)
- November (28)
- October (35)
- September (33)
- August (44)
- July (17)
- June (20)
- May (53)
- April (29)
- March (35)
- February (33)
- January (36)
2009
- December (37)
- November (35)
- October (53)
- September (60)
- August (66)
- July (29)
- June (24)
- May (52)
- April (63)
- March (35)
- February (53)
- January (50)
2008
- December (58)
- November (65)
- October (46)
- September (48)
- August (96)
- July (87)
- June (45)
- May (51)
- April (52)
- March (70)
- February (43)
- January (49)
2007
- December (100)
- November (52)
- October (109)
- September (68)
- August (80)
- July (56)
- June (150)
- May (115)
- April (73)
- March (124)
- February (102)
- January (68)
2006
- December (95)
- November (53)
- October (120)
- September (57)
- August (88)
- July (54)
- June (103)
- May (89)
- April (84)
- March (143)
- February (78)
- January (64)
2005
- December (70)
- November (97)
- October (91)
- September (61)
- August (74)
- July (92)
- June (100)
- May (53)
- April (42)
- March (41)
- February (84)
- January (31)
2004
- December (49)
- November (26)
- October (26)
- September (6)
- April (10)
2025
- January (12)

RavenDB - Version 6.2 Now Live

Oct 23 2006

Object Relational Mapping: You are doing it wrong when...

time to read 2 min | 283 words

You concatenate strings to build dynamic queries.
You have no consistent way of querying the database.
You need to create bad relational model to satisfy the object model that you want.
You have a hard time mapping between the database and the objects, and you are not a beginner.
You goes against well defined concepts such as layering, seperation of concerns, etc.
You need to implement functionality that is already part of the OR/M
You need to do a lot of extra work in order to make the OR/M work correctly.

If any of the above is true for you, STOP! Take a deep breath, and go take a look at the manual. There is a better way.

I believe that I can make OR/M works for 95% of the possible schemas that are out there. And that is a bold statement since I sometimes work with schemas defined for main frames. I also believe that if it is hard to do, it is hard to do because of valid reasons. A good OR/M will steer you in the direction of good database design, when you fight it, it means that there is a problem.

Tweet Share Share 0 comments

Tags:

Comments

Comment preview

Comments have been closed on this topic.

Markdown turns plain text formatting into fancy HTML formatting.

Phrase Emphasis

*italic*   **bold**
_italic_   __bold__

Links

Inline:

An [example](http://url.com/ "Title")

Reference-style labels (titles are optional):

An [example][id]. Then, anywhere
else in the doc, define the link:
  [id]: http://example.com/  "Title"

Images

Inline (titles are optional):

![alt text](/path/img.jpg "Title")

Reference-style:

![alt text][id]
[id]: /url/to/img.jpg "Title"

Headers

Setext-style:

Header 1
========
Header 2
--------

atx-style (closing #'s are optional):

# Header 1 #
## Header 2 ##
###### Header 6

Lists

Ordered, without paragraphs:

1.  Foo
2.  Bar

Unordered, with paragraphs:

*   A list item.
    With multiple paragraphs.
*   Bar

You can nest them:

*   Abacus
    * answer
*   Bubbles
    1.  bunk
    2.  bupkis
        * BELITTLER
    3. burper
*   Cunning

Blockquotes

> Email-style angle brackets
> are used for blockquotes.
> > And, they can be nested.
> #### Headers in blockquotes
> 
> * You can quote a list.
> * Etc.

Horizontal Rules

Three or more dashes or asterisks:

---
* * *
- - - -

Manual Line Breaks

End a line with two or more spaces:

Roses are red,   
Violets are blue.

Fenced Code Blocks

Code blocks delimited by 3 or more backticks or tildas:

```
This is a preformatted
code block
```

Header IDs

Set the id of headings with {#<id>} at end of heading line:

## My Heading {#myheading}

Tables

Fruit    |Color
---------|----------
Apples   |Red
Pears	 |Green
Bananas  |Yellow

Definition Lists

Term 1
: Definition 1
Term 2
: Definition 2

Footnotes

Body text with a footnote [^1]
[^1]: Footnote text here

Abbreviations

MDD <- will have title
*[MDD]: MarkdownDeep

FUTURE POSTS

Partial writes, IO_Uring and safety - 11 hours from now
Configuration values & Escape hatches - 3 days from now
What happens when a sparse file allocation fails? - 5 days from now
NTFS has an emergency stash of disk space - 7 days from now
Challenge: Giving file system developer ulcer - 10 days from now

And 4 more posts are pending...

There are posts all the way to Feb 17, 2025

RECENT SERIES

Challenge (77):
20 Jan 2025 - What does this code do?
Answer (13):
22 Jan 2025 - What does this code do?
Production post-mortem (2):
17 Jan 2025 - Inspecting ourselves to death
Performance discovery (2):
10 Jan 2025 - IOPS vs. IOPS

View all series

RECENT COMMENTS

Dmitry, Yes, but this is _known_ to be a 64 bits system - since we are allocating 3GB (not possible in 64 bits). Note t...

By Oren Eini on Answer: What does this code do?
That's why it is a good idea to compare the return value of `write` to the buffer size. "size_t" can be 32-bit on some system...

By Dmitry on Answer: What does this code do?
There's a reason we miss `write_exact` and `read_exact` from the standard library. In fact, I am surprised the chunk is actua...

By Pyth0n on Challenge: What does this code do?
kpvleeuwen, I agree, unfortunately I don't have anyone to ask off the top of my head. Thanks, I fixed the headers.

By Oren Eini on Performance discovery: IOPS vs. IOPS
It could be interesting to reach out to storage firmware developers and ask what write patterns they think would be useful ex...

By kpvleeuwen on Performance discovery: IOPS vs. IOPS

Syndication

Main feed
Comments feed

}