sqlSave and sqlDrop in R - sql

Question

Here is my code:
library('RODBC')
db.handle <- odbcDriverConnect('driver={SQL Server Native Client 11.0};server=server_name;database = db_name;trusted_connection=yes')
sql_table <- 'db_name.table_name'
sqlDrop(db.handle, sql_table, errors = TRUE)
sqlSave(db.handle,df_small,tablename = sql_table,safer=FALSE,append=TRUE,
rownames = FALSE)
close(db.handle)
When I execute line:
sqlDrop(db.handle, sql_table, errors = TRUE)
I get error message:
Error in odbcTableExists(channel, sqtable, abort = errors) :
‘db_name.table_name’: table not found on channel
When I execute line:
sqlSave(db.handle,df_small,tablename = sql_table,safer=FALSE,append=TRUE,
rownames = FALSE)
I get the following error message:
Error in sqlSave(db.handle, df_small, tablename = sql_table, safer =
FALSE, : 42S01 2714 [Microsoft][SQL Server Native Client 11.0][SQL
Server]
There is already an object named 'table_name' in the database.
[RODBC] ERROR: Could not SQLExecDirect 'CREATE TABLE
db_name.table_name ("State_rename" varchar(255), "CoverageType"
varchar(255))'
I execute code consecutively and cannot understand how both error messages can be true.

Answer 1

Consider removing the schema from the sqltable variable which SQL Server uses with period qualifier. Specifically, change db_name.table_name to table_name. Reason you do not need this schema is your connection handle already specifies the database. With this connection, you cannot access other database schemas in specified server.
library('RODBC')
db.handle <- odbcDriverConnect(paste0('driver={SQL Server Native Client 11.0};',
'server=server_name;database=db_name;trusted_connection=yes'))
sql_table <- 'table_name'
sqlDrop(db.handle, sql_table, errors = TRUE)
sqlSave(db.handle, df_small, tablename = sql_table, safer = FALSE,
append = TRUE, rownames = FALSE)
close(db.handle)
By the way, you can simply use append=FALSE which will overwrite table (first dropping it and then re-creating it) with no need to call sqlDrop:
sqlSave(db.handle, df_small, tablename = sql_table, safer = FALSE,
append = FALSE, rownames = FALSE)