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For base view vql, what does "ESCAPE" mean?

I just observer the vql of the base view (data source is Hadoop Dremio), for the columns whose sourcetypename='CHARACTER VARYING', some has the attribute "ESCAPE NOT SORTABLE" , some has the attribute "NOT SORTABLE", why for the same data type, they have different attributes? what doese "ESCAPE" here mean?
user
25-10-2020 22:52:12 -0400

4 Answers

Hi, if an attribute has assigned an ESCAPE token it means that the associated fields may have certain character that make the Virtual Dataport Server to mandatory send it datasource surronded by the double quotes. it happens mostly for the field name that is a Reserved keyword in the Virtual Dataport Server. To know the reserved keywords, refer to the [Basic primitives for specifying VQL statements](https://community.denodo.com/docs/html/browse/7.0/vdp/vql/language_for_defining_and_processing_data_vql/syntax_conventions/syntax_conventions#basic-primitives-for-specifying-vql-statements) section of the Virtual Dataport VQL Guide. Hope this helps!
Denodo Team
28-10-2020 06:46:14 -0400
get it, so it means the purpose of the "ESCAPE" attribute for this kind of columns, the column name needs to be double quoted because it contains some special charactor of VDP? Do we have the list of this kind of charactor? We need it for some coding about views generated scripts. Thank you.
user
28-10-2020 09:57:58 -0400
Also, I want to understand , for this kind of column, if my vql missing 'ESCAPE' attribute for these kinds of columns but they still double quote, what will happen? Any error or warning or failure if views running? Thank you for lett me know.
user
28-10-2020 10:04:28 -0400
Hi, When a VQL contains an attributes that uses the reserved keyword, it must be surrounded with the double quotes, if not, your VQL deployment will be failed with the following error. > Syntax error: invalid identifier: 'trailing' (reserved keyword) However, when such attribute is surrounded with the double quotes, it is not mandatory to use ESCAPE keyword in wrapper definition and also it will not fail during the query execution. To know the list of reserved keywords, refer to the [Basic primitives for specifying VQL statements](https://community.denodo.com/docs/html/browse/7.0/vdp/vql/language_for_defining_and_processing_data_vql/syntax_conventions/syntax_conventions#basic-primitives-for-specifying-vql-statements) section of the Virtual Dataport VQL Guide. Hope this helps!
Denodo Team
05-11-2020 04:35:49 -0500
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