org.apache.derby.catalog
Interface TypeDescriptor

All Known Implementing Classes:

TypeDescriptorImpl

public interface TypeDescriptor

TypeDescriptor represents a type in a system catalog, a persistent type. Examples are columns in tables and parameters for routines. A TypeDescriptor is immutable.

Field Summary

static TypeDescriptor	INTEGER Catalog type for nullable INTEGER
static TypeDescriptor	INTEGER_NOT_NULL Catalog type for not nullable INTEGER
static int	MAXIMUM_WIDTH_UNKNOWN The return value from getMaximumWidth() for types where the maximum width is unknown.
static TypeDescriptor	SMALLINT Catalog type for nullable SMALLINT
static TypeDescriptor	SMALLINT_NOT_NULL Catalog type for not nullable INTEGER

Method Summary

int	getCollationType() Get the collation type for this type.
int	getJDBCTypeId() Get the jdbc type id for this type.
int	getMaximumWidth() Returns the maximum width of the type.
int	getMaximumWidthInBytes() Returns the maximum width of the type IN BYTES.
int	getPrecision() Returns the number of decimal digits for the type, if applicable.
java.lang.String[]	getRowColumnNames() If this catalog type is a row multi-set type then return its array of column names.
TypeDescriptor[]	getRowTypes() If this catalog type is a row multi-set type then return its array of catalog types.
int	getScale() Returns the number of digits to the right of the decimal for the type, if applicable.
java.lang.String	getSQLstring() Converts this type descriptor (including length/precision) to a string suitable for appearing in a SQL type specifier.
java.lang.String	getTypeName() Gets the name of this type.
boolean	isNullable() Gets the nullability that values of this type have.
boolean	isRowMultiSet() Return true if this is a Row Multiset type
boolean	isUserDefinedType() Return true if this is a user defined type

Field Detail

MAXIMUM_WIDTH_UNKNOWN

static final int MAXIMUM_WIDTH_UNKNOWN

The return value from getMaximumWidth() for types where the maximum width is unknown.

See Also:

Constant Field Values

INTEGER

static final TypeDescriptor INTEGER

Catalog type for nullable INTEGER

INTEGER_NOT_NULL

static final TypeDescriptor INTEGER_NOT_NULL

Catalog type for not nullable INTEGER

SMALLINT

static final TypeDescriptor SMALLINT

Catalog type for nullable SMALLINT

SMALLINT_NOT_NULL

static final TypeDescriptor SMALLINT_NOT_NULL

Catalog type for not nullable INTEGER

Method Detail

getJDBCTypeId

int getJDBCTypeId()

Get the jdbc type id for this type. JDBC type can be found in java.sql.Types.

Returns:

a jdbc type, e.g. java.sql.Types.DECIMAL

See Also:

Types

getMaximumWidth

int getMaximumWidth()

Returns the maximum width of the type. This may have different meanings for different types. For example, with char, it means the maximum number of characters, while with int, it is the number of bytes (i.e. 4).

Returns:

the maximum length of this Type; -1 means "unknown/no max length"

getMaximumWidthInBytes

int getMaximumWidthInBytes()

Returns the maximum width of the type IN BYTES. This is the maximum number of bytes that could be returned for this type if the corresponding getXXX() method is used. For example, if we have a CHAR type, then we want the number of bytes that would be returned by a ResultSet.getString() call.

Returns:

the maximum length of this Type IN BYTES; -1 means "unknown/no max length"

getPrecision

int getPrecision()

Returns the number of decimal digits for the type, if applicable.

Returns:

The number of decimal digits for the type. Returns zero for non-numeric types.

getScale

int getScale()

Returns the number of digits to the right of the decimal for the type, if applicable.

Returns:

The number of digits to the right of the decimal for the type. Returns zero for non-numeric types.

isNullable

boolean isNullable()

Gets the nullability that values of this type have.

Returns:

true if values of this type may be null. false otherwise

getTypeName

java.lang.String getTypeName()

Gets the name of this type.

Returns:

the name of this type

getSQLstring

java.lang.String getSQLstring()

Converts this type descriptor (including length/precision) to a string suitable for appearing in a SQL type specifier. E.g. VARCHAR(30) or java.util.Hashtable

Returns:

String version of type, suitable for running through a SQL Parser.

getCollationType

int getCollationType()

Get the collation type for this type. This api applies only to character string types. And its return value is valid only if the collation derivation of this type is "implicit" or "explicit". (In Derby 10.3, collation derivation can't be "explicit". Hence in Derby 10.3, this api should be used only if the collation derivation is "implicit".

Returns:

collation type which applies to character string types with collation derivation of "implicit" or "explicit". The possible return values in Derby 10.3 will be COLLATION_TYPE_UCS_BASIC and COLLATION_TYPE_TERRITORY_BASED.

See Also:

StringDataValue.COLLATION_TYPE_UCS_BASIC, StringDataValue.COLLATION_TYPE_TERRITORY_BASED

isRowMultiSet

boolean isRowMultiSet()

Return true if this is a Row Multiset type

isUserDefinedType

boolean isUserDefinedType()

Return true if this is a user defined type

getRowTypes

TypeDescriptor[] getRowTypes()

If this catalog type is a row multi-set type then return its array of catalog types.

Returns:

Catalog ypes comprising the row, null if this is not a row type.

getRowColumnNames

java.lang.String[] getRowColumnNames()

If this catalog type is a row multi-set type then return its array of column names.

Returns:

Column names comprising the row, null if this is not a row type.