Max No of Columns allowed in MAXDB 7.5.00.18

[Former Member]

Hello,

How many Maximum No of Columns are allowed for a Table in MaxDB.And also tell me how many bytes a float,double,small int etc takes in MaxDb.

I have seen in help of MaxDB that a table allows 1024 columns including primary key.But the Internal length of a table row is 8088 bytes.But a Long varchar allows 2GB.i don't understand Long Varchar

Size is Greater than Internal length of a table row.Can anyone explain this.

Thanks in Advance,

Venkat

[lbreddemann]

Hi,

in addition to the explanation from Elke, you may want to have a look into a more general description on the topic "data storage in MaxDB".

I recommend you check the documentation and/or the freely available MaxDB Internals Course material:

[http://maxdb.sap.com/training/]

The link

[No-Reorganization Principle; Data Storage Without I/O Bottlenecks|http://maxdb.sap.com/training/internals_7.6/reorgfree_EN_76.pdf]

points to a quite complete description of how MaxDB stores data.

Best regards,

Lars

[Former Member]

Hi,

in the reference manual chapter Data definition -> create table -> column definition -> data type -> Memory Requirements ... you will find a full description of the needed number of bytes for each datatype.

And there you will see, that for LONG columns exactly 9 bytes are used, because some identification and not the value itself is stored in a record.

Elke