RODBC (version 1.2-3)

RODBCtables: Operations on Tables in ODBC databases

Description

Operations on tables in ODBC databases.

Usage

sqlClear(channel, sqtable, errors = TRUE)
sqlDrop(channel, sqtable, errors = TRUE)
sqlColumns(channel, sqtable, errors = FALSE, as.is = TRUE,
           special = FALSE)
sqlPrimaryKeys(channel, sqtable, errors = FALSE, as.is = TRUE)

Arguments

channel

connection object as returned by odbcConnect.

sqtable

character: a database table name accessible from the connected dsn.

errors

if TRUE halt and display error, else return -1

as.is

as in sqlGetResults.

special

return only the column(s) needed to specify a row uniquely. Depending on the database, there might be none.

Value

• A data frame on success, or character/numeric on error depending on the errors parameter. If no data is returned, either a zero-row data frame or an error. (For example, if there are no primary keys or special column(s) in this table an empty data frame is returned, but if primary keys are not supported by the DBMS, an error code results.)

Details

sqlClear deletes the content of the table sqtable. No confirmation is requested.

sqlDrop removes the table sqtable. No confirmation is requested.

sqlColumns and sqlPrimaryKeys return information as data frames. The column names are not constant across ODBC versions so the data should be accessed by column number. The argument special to sqlColumns returns the columns needed to specify a row uniquely. This is intended to form the basis of a WHERE clause for updates (see sqlUpdate).

See Also

odbcConnect, sqlQuery, sqlFetch, sqlSave, sqlTables, odbcGetInfo

Examples

## example results from MySQL
channel <- odbcConnect("test")
sqlDrop(channel, "USArrests", errors = FALSE) # precautionary
sqlSave(channel, USArrests)
sqlColumns(channel, "USArrests")
sqlColumns(channel, "USArrests", special = TRUE)
sqlPrimaryKeys(channel, "USArrests")
sqlColumns(channel, "USArrests")
##   Table_cat Table_schema Table_name Column_name Data_type Type_name
## 1                         USArrests    rownames        12   varchar
## 2                         USArrests      murder         8    double
## 3                         USArrests     assault         4   integer
## 4                         USArrests    urbanpop         4   integer
## 5                         USArrests        rape         8    double
##   Column_size Buffer_length Decimal_digits Num_prec_radix Nullable Remarks
## 1         255           255           <NA>           <NA>        0
## 2          22             8             31             10        1
## 3          11             4              0             10        1
## 4          11             4              0             10        1
## 5          22             8             31             10        1
sqlColumns(channel, "USArrests", special = TRUE)
##   Scope Column_name Data_type Type_name Precision Length Scale
## 1     2    rownames        12   varchar         0      0     0
##   Pseudo_column
## 1             1
sqlPrimaryKeys(channel, "USArrests")
##   Table_qualifer Table_owner Table_name Column_name Key_seq Pk_name
## 1           <NA>        <NA>  USArrests    rownames       1 PRIMARY
sqlClear(channel, "USArrests")
sqlDrop(channel, "USArrests")
close(channel)