mysqlSupport: Support Functions

Description

These functions are the workhorse behind the RMySQL package, but users need not invoke these directly. For details see MySQL.

Usage

## MySQLDriver-related
   mysqlInitDriver(max.con=16, fetch.default.rec = 500, force.reload=FALSE)
   mysqlDriverInfo(obj, what, ...)
   mysqlDescribeDriver(obj, verbose = FALSE, ...)
   mysqlCloseDriver(drv, ...)
   ## MySQLConnection-related
   mysqlNewConnection(drv, dbname, username, password, host, unix.socket,
         port, client.flag, groups)
   mysqlCloneConnection(con, ...)
   mysqlConnectionInfo(obj, what, ...)
   mysqlDescribeConnection(obj, verbose = FALSE, ...)
   mysqlCloseConnection(con, ...)
   ## MySQLResult-related
   mysqlExecStatement(con, statement)
   mysqlFetch(res, n=0, ...)
   mysqlQuickSQL(con, statement)
   mysqlResultInfo(obj, what, ...)
   mysqlDescribeResult(obj, verbose = FALSE, ...)
   mysqlCloseResult(res, ...)
   mysqlDescribeFields(res, ...)
   ## data mappings, convenience functions, and extensions
   mysqlDataType(obj, ...)
   mysqlReadTable(con, name, row.names = "row.names", check.names = TRUE, ...)
   mysqlWriteTable(con, name, value, field.types, row.names = TRUE, 
      overwrite=FALSE, append=FALSE, ..., allow.keywords = FALSE)

Arguments

max.con

positive integer specifying maximum number of open connections. The current default of 10 is hardcoded in the C code.

fetch.default.rec

default number of rows to fetch (move to R/S-Plus). This default is used in mysqlFetch. The default is 500.

force.reload

logical indicating whether to re-initialize the driver. This may be useful if you want to change the defaults (e.g., fetch.default.rec). Note that the driver is a singleton (subsequent inits just returned the previously initialized

obj

any of the MySQL DBI objects (e.g., MySQLConnection, MySQLResult).

what

character vector of metadata to extract, e.g., "version", "statement", "isSelect".

verbose

logical controlling how much information to display. Defaults to FALSE.

drv

an MySQLDriver object as produced by mysqlInitDriver.

con

an MySQLConnection object as produced by mysqlNewConnection and mysqlCloneConnection.

res

an MySQLResult object as produced by by mysqlExecStatement.

username

a character string with the MySQL's user name.

password

character string with the MySQL's password.

groups

character vector with one or more MySQL group names. For details see MySQL.

dbname

character string with the MySQL database name.

host

character string with the name (or IP address) of the machine hosting the database. Default is "", which is interpreted as localhost by the MySQL's API.

unix.socket

(optional) character string with a filename for the socket file name. Consult the MySQL documentation for details.

port

(optional) positive integer specifying the TCP port number that the MySQL server is listening to. Consult the MySQL documentation for details.

client.flag

(optional) integer setting flags for the client. Consult the MySQL documentation for details.

force

logical indicating whether to close a connection that has open result sets. The default is FALSE.

statement

character string holding one (and only one) SQL statement.

number of rows to fetch from the given result set. A value of -1 indicates to retrieve all the rows. The default of 0 specifies to extract whatever the fetch.default.rec was specified during driver initialization mysqlInit

name

character vector of names (table names, fields, keywords).

value

a data.frame.

field.types

a list specifying the mapping from R/S-Plus fields in the data.frame value to SQL data types. The default is sapply(value,SQLDataType), see MySQLSQLType.

row.names

a logical specifying whether to prepend the value data.frame row names or not. The default is TRUE.

check.names

a logical specifying whether to convert DBMS field names into legal S names. Default is TRUE.

overwrite

logical indicating whether to replace the table name with the contents of the data.frame value. The defauls is FALSE.

append

logical indicating whether to append value to the existing table name.

allow.keywords

logical indicating whether column names that happen to be MySQL keywords be used as column names in the resulting relation (table) being written. Defaults to FALSE, forcing mysqlWriteTable to modify column names to make

...

placeholder for future use.

Value

mysqlInitDriver returns an MySQLDriver object.
mysqlDriverInfo returns a list of name-value metadata pairs.
mysqlDescribeDriver returns NULL (displays the object's metadata).
mysqlCloseDriver returns a logical indicating whether the operation succeeded or not.
mysqlNewConnection returns an MySQLConnection object.
mysqlCloneConnection returns an MySQLConnection object.
mysqlConnectionInforeturns a list of name-value metadata pairs.
mysqlDescribeConnection returns NULL (displays the object's metadata).
mysqlCloseConnection returns a logical indicating whether the operation succeeded or not.
mysqlExecStatement returns an MySQLResult object.
mysqlFetch returns a data.frame.
mysqlQuickSQL returns either a data.frame if the statement is a select-like or NULL otherwise.
mysqlDescribeResult returns NULL (displays the object's metadata). mysqlCloseResult returns a logical indicating whether the operation succeeded or not. mysqlDescribeFields returns a data.frame with one row per field with columns name, Sclass, type, len, precision, scale, and nullOK which fully describe each field in a result set. Except for Sclass (which shows the mapping of the field type into an R/S-Plus class) all the information pertains to MySQL's data storage attributes.
mysqlReadTable returns a data.frame with the contents of the DBMS table. mysqlWriteTable returns a logical indicating whether the operation succeeded or not. mysqlDataType retuns a character string with the closest mysqlResultInfo returns a list of name-value metadata pairs.

Constants

.MySQLPkgName (currently "RMySQL"), .MySQLPkgVersion (the R package version), .MySQLPkgRCS (the RCS revision), .MySQL.NA.string (character that MySQL uses to denote NULL on input), .MySQLSQLKeywords (a lot!) .conflicts.OK.