Provided by: libopendbx1-dev_1.4.6-9build1_amd64 
NAME
OpenDBX::Result - Provides result sets from the database.
SYNOPSIS
Public Member Functions
unsigned long columnCount () throw ( std::exception )
Returns the number of columns available in this result set.
const string columnName (unsigned long pos) throw ( std::exception )
Returns the name of the column in the current result set.
unsigned long columnPos (const string &name) throw ( std::exception )
Maps the column name to the column number required by other methods.
odbxtype columnType (unsigned long pos) throw ( std::exception )
Returns the type of the column in the current result set.
unsigned long fieldLength (unsigned long pos) throw ( std::exception )
Returns the size of the content in the current row at the specified postion.
const char * fieldValue (unsigned long pos) throw ( std::exception )
Returns a pointer to the content in the current row at the specified postion.
void finish () throw ( std::exception )
Retrieves unfetched rows and cleans up the available result sets.
Lob getLob (const char *value) throw ( std::exception )
Creates a large object instance if supported by the database.
odbxres getResult (struct timeval *timeout=NULL, unsigned long chunk=0) throw (
std::exception )
Fetches one result set from the database server.
odbxrow getRow () throw ( std::exception )
Makes data of next row available.
Result & operator= (const Result &ref) throw ()
Assigns a Result instance to another one.
Result (const Result &ref) throw ()
Copy constructor.
uint64_t rowsAffected () throw ( std::exception )
Returns the number of rows affected by DELETE, INSERT of UPDATE statements.
~Result () throw ()
Destroys a Result instance if no other references exist.
Protected Member Functions
Result () throw ()
Default constructor.
Result (Result_Iface *impl) throw ( std::exception )
Creates a Result instance.
Detailed Description
Provides result sets from the database.
Author:
Norbert Sendetzky norbert@linuxnetworks.de
Version:
1.0
Constructor & Destructor Documentation
OpenDBX::Result::Result () [inline], [protected]
Default constructor. The default constructor isn't part of the public interface as the
object must not be created manually. Instead, the Stmt::execute() method is a factory for
instances of the Result class.
Returns:
Result instance
OpenDBX::Result::Result (Result_Iface * impl)std::exception [protected]
Creates a Result instance. The constructor isn't part of the public interface as the
object must not be created manually. Instead, the Stmt::execute() method is a factory for
instances of the Result class.
Parameters:
impl Pointer to private implementation
Exceptions:
std::exception If an error occures
Returns:
Result instance
OpenDBX::Result::~Result ()
Destroys a Result instance if no other references exist. Each result object uses a
reference counter to remember if the internal variables are shared with other objects. If
this isn't the case or if this object is the last one referencing the variables, the
object is cleanup up and the allocated memory freed.
OpenDBX::Result::Result (const Result & ref)
Copy constructor. Enables the transfer of the internal state of an object ref of the same
type to this object. Both objects share the same variables and the reference counter
afterwards. The reference counter is incremented each time an object is copied and will be
decremented if it is destroyed.
Parameters:
ref Original result object instance
Member Function Documentation
unsigned long OpenDBX::Result::columnCount ()std::exception
Returns the number of columns available in this result set. The number of columns will
never change within a result set with one notable exception: MySQL returns all outstanding
rows of a previous result set first if they were not fetched completely by getRow()
before. Therefore, the column count might change in this special situation.
Returns:
Number of columns
Exceptions:
OpenDBX::Exception If the underlying database library returns an error
const string OpenDBX::Result::columnName (unsigned long pos)std::exception
Returns the name of the column in the current result set. Gets the name of the column
specified by pos in the current result set. The column names will not change within the
result set with the exception of MySQL when the first result set wasn't retrieved
completely before getResult() was called again.
Parameters:
pos Position of column in result set
Returns:
Column name
Exceptions:
OpenDBX::Exception If the underlying database library returns an error
unsigned long OpenDBX::Result::columnPos (const string & name)std::exception
Maps the column name to the column number required by other methods. This method returns
the index of the column which is named like the content of the string given via the
parameter name. The column index will not change within the result set.
Parameters:
name Name of the column in the result set
Returns:
Position of column in result set
Exceptions:
OpenDBX::Exception If the underlying database library returns an error
odbxtype OpenDBX::Result::columnType (unsigned long pos)std::exception
Returns the type of the column in the current result set. The column type applies to all
fields at the same position of the rows fetched via getRow(). The definitions are based on
the SQL2003 standard and the data types of the database server have to comply to the
specification of the standard. These are:
Exact numeric values:
• ODBX_TYPE_BOOLEAN: True/false values
• ODBX_TYPE_SMALLINT: Signed 16 bit integer
• ODBX_TYPE_INTEGER: Signed 32 bit integer
• ODBX_TYPE_BIGINT: Signed 64 bit integer
• ODBX_TYPE_DECIMAL: Exact signed numeric values with user defined precision
Approximate numeric values:
• ODBX_TYPE_REAL: Approximate numeric values (signed) with 32 bit precision
• ODBX_TYPE_DOUBLE: Approximate numeric values (signed) with 64 bit precision
• ODBX_TYPE_FLOAT: Approximate numeric values (signed) with user defined precision
String values:
• ODBX_TYPE_CHAR: Fixed number of characters
• ODBX_TYPE_NCHAR: Fixed number of characters using a national character set
• ODBX_TYPE_VARCHAR: Variable number of characters
• ODBX_TYPE_NVARCHAR: Variable number of characters using a national character set
Large objects:
• ODBX_TYPE_CLOB: Large text object
• ODBX_TYPE_NCLOB: Large text object using a national character set
• ODBX_TYPE_XML: XML tree in text format
• ODBX_TYPE_BLOB: Large binary object
Date and time values:
• ODBX_TYPE_TIME: Time including hours, minutes and seconds
• ODBX_TYPE_TIME_TZ: Time with timezone information
• ODBX_TYPE_TIMESTAMP: Date and time
• ODBX_TYPE_TIMESTAMP_TZ: Date and time with timezone information
• ODBX_TYPE_DATE: Date including year, month and day
• ODBX_TYPE_INTERVAL: Date interval
Arrays and sets:
• ODBX_TYPE_ARRAY: Array of values
• ODBX_TYPE_MULTISET: Associative arrays
External links:
• ODBX_TYPE_DATALINK: URI locators like URL links
Data types provided by database implementations which are not covered by the SQL2003
standard are subsumed as ODBX_TYPE_UNKNOWN.
Parameters:
pos Position of column in result set
Returns:
Column type
Exceptions:
OpenDBX::Exception If the underlying database library returns an error
See also:
odbxtype
unsigned long OpenDBX::Result::fieldLength (unsigned long pos)std::exception
Returns the size of the content in the current row at the specified postion. The field is
part of the current row which was retrieved by the latest call to getRow() and is
specified by the column index given by pos.
Parameters:
pos Position of column in result set
Returns:
Size of the data in bytes
Exceptions:
OpenDBX::Exception If the underlying database library returns an error
const char* OpenDBX::Result::fieldValue (unsigned long pos)std::exception
Returns a pointer to the content in the current row at the specified postion. This
function returns a pointer to the field data specified by the column index pos. The field
is part of the current row which was retrieved by the latest call to getRow(). All values
except binary objects are handed back as strings terminated by the zero character. This
does also apply to numeric values, dates, etc. They have to be converted to their binary
machine dependent representation before arithmetic operations can be done. If a value is
undefined, i.e. 'NULL' is attached to the field in the database, an equivalent NULL
pointer is returned.
Parameters:
pos Position of column in result set
Returns:
Pointer to the data
Exceptions:
OpenDBX::Exception If the underlying database library returns an error
void OpenDBX::Result::finish ()std::exception
Retrieves unfetched rows and cleans up the available result sets. After executing a
statement, at least one result set is returned by the database server. In case of data
manipulation statements, there are no rows returned but you have to clean up the result
set nevertheless. This is usually done by calling and getResult() in a loop until it
returns 'done'. In order to simplify application development, the finish() method does
this for you.
Exceptions:
OpenDBX::Exception If the underlying database library returns an error
Lob OpenDBX::Result::getLob (const char * value)std::exception
Creates a large object instance if supported by the database. Returns a Lob class instance
representing a large object stored in the database. It references the large object and
provided methods for accessing and modifying its content.
The parameter required by this method must be the value returned by the fieldValue()
method of a large object column.
This method must only be used if the underlying driver states that it supports large
objects via the Conn::getCapabilities(). Otherwise, the content can be retrieved directly
by the fieldValue() method.
Parameters:
value Pointer to the content of a field returned by fieldValue()
Returns:
Large object instance
Exceptions:
OpenDBX::Exception If the underlying database library returns an error
See also:
Lob
odbxres OpenDBX::Result::getResult (struct timeval * timeout = NULL, unsigned long chunk =
0)std::exception
Fetches one result set from the database server. Retrieves the result of a query statement
from the database server. If the statement was an INSERT, UPDATE, DELETE or a similar
statement, the number of affected rows is available via rowsAffected().
The timeout parameter restricts the time the function is waiting for a result form the
server. It may be NULL to wait until a result arrives. Otherwise, it can contain any
number of seconds and microseconds in a timeval structure to wait for. The timeval
structure must be set each time before calling getResult() because its content may get
changed by the function. If the server doesn't respond within the timeout, the query isn't
canceled! Instead, the next call to this function will wait for the same result set.
Waiting the specified time may be implemented in the backends if it is possible, but there
is no guarantee. If not, getResult() will return not before a responds arrives.
Dependent on the native database library, it may be possible to retrieve all rows at once
(if chunk is zero), one by one or more than one row at once. All positive values including
zero are allowed as values for chunk If paging (more than one row at once) is not
supported by the backend, it will use 'one by one' or 'all at once' if this is the only
option provided.
getResult() returns ODBX_RES_ROWS if a result set is available and ODBX_RES_DONE if no
more results will be returned by the last successful query. ODBX_RES_NOROWS is returned if
the statement was executed successfully but will not return a results set (like for
INSERT, UPDATE and DELETE statements) and ODBX_RES_TIMEOUT indicates a timeout.
Parameters:
timeout Pointer to a timeval struct specifying how long to wait for a result set from
the database server
chunk Number of rows to fetch at once from the database server (zero means all rows at
once)
Returns:
Status or error code
Exceptions:
OpenDBX::Exception If the underlying database library returns an error
See also:
odbxres
odbxrow OpenDBX::Result::getRow ()std::exception
Makes data of next row available. Retrieves the values of a row from the current result
set returned by getResult(). Until this function is invoked, no row and field data is
available via fieldLength() or fieldValue() and these functions will throw an exception.
getRow() will return ODBX_ROW_NEXT as long as rows are available from the result set.
After the last row has been made available, further calls to this function will return
ODBX_ROW_DONE indicating that the result set doesn't contain more rows.
Returns:
Status of the attempt to fetch one more row
Exceptions:
OpenDBX::Exception If the underlying database library returns an error
Result& OpenDBX::Result::operator= (const Result & ref)
Assigns a Result instance to another one. Assigns the internal state of an object ref of
the same type to this object. Both objects share the same variables and the reference
counter afterwards. The reference counter is incremented each time an object is copied and
will be decremented if it is destroyed.
Parameters:
ref Result instance
Returns:
Result reference of this instance
uint64_t OpenDBX::Result::rowsAffected ()std::exception
Returns the number of rows affected by DELETE, INSERT of UPDATE statements. Returns the
number of rows that have been changed by the current statement whose result set was
retrieved by getResult() and zero if the database server didn't alter any rows. Affected
rows are only returned for DELETE, INSERT or UPDATE statements and their concrete number
depends on the database implementation. Some database server like MySQL may return a lower
number than expected because they doesn't modify records whose values wouldn't change.
Returns:
Number of rows touched
Exceptions:
OpenDBX::Exception If the underlying database library returns an error
Author
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