MetaData Class

A MetaData object can be used to describe the types and properties of the columns in a ResultSet or the existing schema objects in the database. It also provides information about the database as a whole. The parameter types for objects are listed in Table 10-24.

Table 10-24 Parameter Types for Objects

Parameter Type	Description
PTYPE_ARG	argument of a function or procedure
PTYPE_COL	column of a table or view
PTYPE_DATABASE	database
PTYPE_FUNC	function
PTYPE_PKG	package
PTYPE_PROC	procedure
PTYPE_SCHEMA	schema
PTYPE_SEQ	sequence
PTYPE_SYN	synonym
PTYPE_TABLE	table
PTYPE_TYPE	type
PTYPE_TYPE_ARG	argument of a type method
PTYPE_TYPE_ATTR	attribute of a type
PTYPE_TYPE_COLL	collection type information
PTYPE_TYPE_METHOD	method of a type
PTYPE_TYPE_RESULT	results of a method
PTYPE_TYPE_UNK	object of an unknown type
PTYPE_TYPE_VIEW	view

Attribute values are returned on executing a getxxx() method, passing some attribute for which these are the results:

Table 10-25 Enumerated Values of Attributes for MetaData Class

Attribute Value	Description
DURATION_SESSION	Duration of a temporary table: session
DURATION_TRANS	Duration of a temporary table: transaction
DURATION_NULL	Duration of a temporary table: table not temporary
TYPEENCAP_PRIVATE	Encapsulation level of the method: private
TYPEENCAP_PUBLIC	Encapsulation level of the method: public
TYPEPARAM_IN	Argument mode: `IN`
TYPEPARAM_OUT	Argument mode: `OUT`
TYPEPARAM_INOUT	Argument mode: `IN/OUT`
CURSOR_OPEN	Effect of `COMMIT` operation on cursors and prepared statements in the database: preserve cursor state as before the `COMMIT` operation
CURSER_CLOSED	Effect of `COMMIT` operation on cursors and prepared statements in the database: cursors are closed on `COMMIT`, but the applicaton can still reexecute the statement without re-preparing it
CL_START	Position of the catalog in a qualified table: start
CL_END	Position of the catalog in a qualified table: end
SP_SUPPORTED	Database supports savepoints
SP_UNSUPPORTED	Database does not support savepoints
NW_SUPPORTED	Database supports nowait clause
NW_UNSUPPORTED	Database does not supports nowait clause
AC_DDL	Autocommit mode required for DDL statements
NO_AC_DDL	Autocommit mode not required for DDL statements
LOCK_IMMEDIATE	Locking mode for the database: immediate
LOCK_DELAYED	Locking mode for the database: delayed

Table 10-26 Summary of MetaData Methods

Method	Description
MetaData()	`MetaData` class constructor.
getAttributeCount()	Gets the count of the attribute as a `MetaData` object
getAttributeId()	Gets the ID of the specified attribute
getAttributeType()	Gets the type of the specified attribute.
getBoolean()	Gets the value of the attribute as a C++ `boolean`.
getInt()	Gets the value of the attribute as a C++ `int`.
getMetaData()	Gets the value of the attribute as a `MetaData` object
getNumber()	Returns the specified attribute as a `Number` object.
getRef()	Gets the value of the attribute as a `Ref<T>`.
getString()	Gets the value of the attribute as a string.
getTimeStamp()	Gets the value of the attribute as a `Timestamp` object
getUInt()	Gets the value of the attribute as a C++ `unsigned int`.
getUString()	Return the value of the attribute as a `UString` in the character set associated with the metadata.
getVector()	Gets the value of the attribute as an C++ vector.
operator=()	Assigns one metadata object to another.

MetaData()

MetaData class constructor.

Syntax

MetaData(
   const MetaData &omd);

Parameter	Description
cmd	The source that the `MetaData` object will be copied from.

getAttributeCount()

This method returns the number of attributes related to the metadata object.

Syntax

unsigned int getAttributeCount() const;

getAttributeId()

This method returns the attribute ID (ATTR_NUM_COLS, . . . ) of the attribute represented by the attribute number specified.

Syntax

AttrId getAttributeId(
   unsigned int attributeNum) const;

Parameter	Description
attributeNum	The number of the attribute for which the attribute ID is to be returned.

getAttributeType()

This method returns the attribute type (NUMBER, INT, . . . ) of the attribute represented by attribute number specified.

Syntax

Type getAttributeType(
   unsigned int attributeNum) const;

Parameter	Description
attributeNum	The number of the attribute for which the attribute type is to be returned.

getBoolean()

This method returns the value of the attribute as a C++ boolean. If the value is a SQL NULL, the result is FALSE.

Syntax

bool getBoolean(
   MetaData::AttrId attributeId) const;

Parameter	Description
attributeId	The attribute ID

getInt()

This method returns the value of the attribute as a C++ int. If the value is SQL NULL, the result is 0.

Syntax

int getInt(
   MetaData::AttrId attributeId) const;

Parameter	Description
attributeId	The attribute ID

getMetaData()

This method returns a MetaData instance holding the attribute value. A metadata attribute value can be retrieved as a MetaData instance. This method can only be called on attributes of the metadata type.

Syntax

MetaData getMetaData(
   MetaData::AttrId attributeId) const;

Parameter	Description
attributeId	The attribute ID

getNumber()

This method returns the value of the attribute as a Number object. If the value is a SQL NULL, the result is NULL.

Syntax

Number getNumber(
   MetaData::AttrId attributeId) const;

Parameter	Description
attributeId	The attribute ID

getRef()

This method returns the value of the attribute as a RefAny, or Ref to a TDO. If the value is SQL NULL, the result is NULL.

Syntax

RefAny getRef(
   MetaData::AttrId attributeId) const;

Parameter	Description
attributeId	The attribute ID

getString()

This method returns the value of the attribute as a string. If the value is SQL NULL, the result is NULL.

Syntax

string getString(
   MetaData::AttrId attributeId) const;

Parameter	Description
attributeId	The attribute ID

getTimeStamp()

This method returns the value of the attribute as a Timestamp object. If the value is a SQL NULL, the result is NULL.

Syntax

Timestamp getTimestamp(
   MetaData::AttrId attributeId) const;

Parameter	Description
attributeId	The attribute ID

getUInt()

This method returns the value of the attribute as a C++ unsigned int. If the value is a SQL NULL, the result is 0.

Syntax

unsigned int getUInt(
   MetaData::AttrId attributeId) const;

Parameter	Description
attributeId	The attribute ID

getUString()

Return the value of an attribute as a UString in the character set associated with the metadata.

Syntax

UString getUString(
   MetaData::AttrId attributeId) const;

Parameter	Description
attributeId	The attribute ID

getVector()

This method returns a C++ vector containing the attribute value. A collection attribute value can be retrieved as a C++ vector instance. This method can only be called on attributes of a list type.

Syntax

vector<MetaData> getVector(
   MetaData::AttrId attributeId) const;

Parameter	Description
attributeId	The attribute ID

operator=()

This method assigns one MetaData object to another. This increments the reference count of the MetaData object that is assigned.

Syntax

void operator=(
   const MetaData &omd);

Parameter	Description
cmd	MetaData object to be assigned