nbenn opened a new issue, #1365:
URL: https://github.com/apache/arrow-adbc/issues/1365
DBI requires me to return a zero-row `data.frame` when binding zero-length
parameters in a parametrized query. For something like
```r
library(DBI)
con <- dbConnect(adbi::adbi("adbcsqlite"), uri = ":memory:")
dbWriteTable(con, "swiss", datasets::swiss)
res <- dbSendQuery(con, "SELECT * from swiss WHERE Agriculture < ?")
dbBind(res, list(integer()))
dbFetch(res)
```
I'd need to return something like
```r
swiss[0, ]
#> [1] Fertility Agriculture Examination Education
#> [5] Catholic Infant.Mortality
#> <0 rows> (or 0-length row.names)
```
but instead I currently have an error `Error parsing schema->format:
Expected a null-terminated string but found NULL`.
One way for me to do this is by catching the zero-length parameter binding
and constructing the zero-length `data.frame` from the result schema. To do
this, I'd need to access the result schema without binding/executing.
We have the exported function `adbc_statement_execute_schema()` available.
Does that possibly do what I need it to? Unfortunately, I get
```r
library(adbcdrivermanager)
db <- adbc_database_init(adbcsqlite::adbcsqlite(), uri = ":memory:")
con <- adbc_connection_init(db)
write_adbc(datasets::swiss, con, "swiss", temporary = TRUE)
stmt <- adbc_statement_init(con)
adbc_statement_set_sql_query(stmt, "SELECT * from swiss WHERE Agriculture <
?")
adbc_statement_prepare(stmt)
adbc_statement_execute_schema(stmt)
#> Error in adbc_statement_execute_schema(stmt) : NOT_IMPLEMENTED
```
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