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From Benjamin Black...@b3k.us>
Subject Re: Nodes Levels of Hierarchy in Cassandra.
Date Sun, 16 May 2010 22:07:47 GMT
Not in Cassandra.

Your description of the levels is not quite accurate, either.  The
keyspaces and CFs are generally considered fixed since it is rather
expensive to change them compared to the row keys and columns.  Within
an SCF, you have:

row_key: {supercolumn1: {column1A: value1A, column1B: value1B},
supercolumn2: {column2A: value2A, column2B: value2B}}

So the 3 levels of the hierarchy with SCFs are row
key->supercolumn->column.  You can certainly treat the SCF itself as a
4th level of the hierarchy if you like, but don't expect to add and
remove them as you do the 3 'dynamic' levels.


b

On Tue, May 11, 2010 at 8:51 AM,  <xmanach.ext@orange-ftgroup.com> wrote:
> Hi.
>
>   I undertstood I can use this structure with cassandra :
>
> KeySpace_3nodeslevels = {
>     Key_Family_alfa : {
>         Key_Super_Column_A : { Key_Column_1: "Value_alfa_A_1",
>                                Key_Column_2: "Value_alfa_A_2"},
>         Key_Super_Column_B : { Key_Column_1: "Value_alfa_B_1",
>                                Key_Column_2: "Value_alfa_B_2"}
},
>     Key_Family_beta : {
>         Key_Super_Column_A : { Key_Column_1: "Value_beta_A_1",
>                                Key_Column_2: "Value_beta_A_2"},
>         Key_Super_Column_B : { Key_Column_1: "Value_beta_B_1",
>                                Key_Column_2: "Value_beta_B_2"}
}
>              }
>
> I have 3 nodes levels of hierarchy for the keys : Key_Family,
> Key_Super_Column and  Key_Column.
> I have around 100 Billions of keys for the Family level.
>
>   Can I have 4 nodes levels of hierarchy like this ?
>
> KeySpace_4nodeslevels = {
>     Key_level1_alfa : {
>         Key_level2_A : { Key_level3_1: { Key_level4_first  :
> "Value_alfa_A_1_first",
>                                          Key_level4_Second
:
> "Value_alfa_A_1_second"},
>                          Key_level3_2: { Key_level4_first  :
> "Value_alfa_A_2_first",
>                                          Key_level4_Second
:
> "Value_alfa_A_2_second"} },
>         Key_level2_B : { Key_level3_1: { Key_level4_first  :
> "Value_alfa_B_1_first",
>                                          Key_level4_Second
:
> "Value_alfa_B_1_second"},
>                          Key_level3_2: { Key_level4_first  :
> "Value_alfa_B_2_first",
>                                          Key_level4_Second
:
> "Value_alfa_B_2_second"} } },
>     Key_level1_beta : {
>         Key_level2_A : { Key_level3_1: { Key_level4_first  :
> "Value_beta_A_1_first",
>                                          Key_level4_Second
:
> "Value_beta_A_1_second"},
>                          Key_level3_2: { Key_level4_first  :
> "Value_beta_A_2_first",
>                                          Key_level4_Second
:
> "Value_beta_A_2_second"} },
>         Key_level2_B : { Key_level3_1: { Key_level4_first  :
> "Value_beta_B_1_first",
>                                          Key_level4_Second
:
> "Value_beta_B_1_second"},
>                          Key_level3_2: { Key_level4_first  :
> "Value_beta_B_2_first",
>                                          Key_level4_Second
:
> "Value_beta_B_2_second"} } }
>         }
>
> Thanks.
>
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