describe {RMySQL}R Documentation

Describe an object through its meta-data

Description

Prints a concise description of the meta-data associated with an object

Usage

describe(obj, verbose, ...)

Arguments

obj any object that implements some functionality under the R/S interface to databases, e.g., dbManager, dbConnection, dbResultSet, resultSet.
verbose a logical controling the amount of output.
... any other argument that the individual methods may take.

Value

NULL

Side Effects

This function is used mainly for its printing side effects.

References

See the Omega Project for Statistical Computing at http://www.omegahat.org for more details on the R/S database interface.

See Also

On database managers:

dbManager MySQL load unload

On connections, SQL statements and resultSets:

dbExecStatement dbExec fetch quickSQL

On transaction management:

commit rollback Ora On meta-data:

describe getVersion getDatabases getTables getFields getCurrentDatabase getTableIndices getException getStatement hasCompleted getRowCount getAffectedRows getNullOk getInfo

Examples

> m <- dbManager("Oracle")
> ...
# Let's look at the status of the manager

> describe(m, verbose = F)   
OraManager id = (7269) 
  Max  connections: 16 
  Conn. processed: 1 
  Default records per fetch: 500 
  Open connections: 1 

> rs <- dbExecStatement(con, query)
> ...

# The following shows that we extracted only one field
# names "Tables in opto" plus its corresponding S class, internal 
# database type, and various other internal attributes.

> getFields(rs)
           name    Sclass              type len precision scale nullOK 
1 Tables in opto character FIELD_TYPE_STRING  64        64     0      F

# A full description of the result set is

> describe(rs, verbose = T)
OraResultSet id = (7269,3,1) 
  Statement: show tables 
  Has completed? no 
  Affected rows: -1 
  Rows fetched: 3 
  Fields:
            name    Sclass              type len precision scale nullOK 
1 Tables in opto character FIELD_TYPE_STRING  64        64     0      F
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