org.apache.derby.vti

Class VTIMetaDataTemplate

java.lang.Object

org.apache.derby.vti.VTIMetaDataTemplate

All Implemented Interfaces:

java.sql.ResultSetMetaData, java.sql.Wrapper

public abstract class VTIMetaDataTemplate
extends java.lang.Object
implements java.sql.ResultSetMetaData

An abstract implementation of ResultSetMetaData (JDBC 1.2) that is useful when writing a VTI (virtual table interface). This class implements most of the methods of ResultSetMetaData, each one throwing a SQLException with the name of the method. A concrete subclass can then just implement the methods not implemented here and override any methods it needs to implement for correct functionality.

The methods not implemented here are

• getColumnCount()
• getColumnType()

For virtual tables the database engine only calls methods defined in the JDBC 1.2 definition of java.sql.ResultSetMetaData.
Classes that implement a JDBC 2.0 conformant java.sql.ResultSetMetaData can be used as the meta data for virtual tables.
Developers can use the VTIMetaDataTemplate20 instead of this class when developing in a Java 2 environment.

Field Summary

Fields inherited from interface java.sql.ResultSetMetaData

columnNoNulls, columnNullable, columnNullableUnknown

Constructor Summary

Constructors

Constructor and Description
VTIMetaDataTemplate()

Method Summary

Modifier and Type	Method and Description
java.lang.String	getCatalogName(int column) What's a column's table's catalog name?
java.lang.String	getColumnClassName(int column) Returns the fully-qualified name of the Java class whose instances are manufactured if the method ResultSet.getObject is called to retrieve a value from the column.
int	getColumnDisplaySize(int column) What's the column's normal maximum width in chars?
java.lang.String	getColumnLabel(int column) What's the suggested column title for use in printouts and displays?
java.lang.String	getColumnName(int column) What's a column's name?
java.lang.String	getColumnTypeName(int column) What's a column's data source specific type name?
int	getPrecision(int column) How many decimal digits are in the column?
int	getScale(int column) What's a column's number of digits to the right of the decimal point?
java.lang.String	getSchemaName(int column) What's a column's table's schema?
java.lang.String	getTableName(int column) What's a column's table name?
boolean	isAutoIncrement(int column) Is the column automatically numbered, and thus read-only?
boolean	isCaseSensitive(int column) Does a column's case matter?
boolean	isCurrency(int column) Is the column a cash value?
boolean	isDefinitelyWritable(int column) Will a write on the column definitely succeed?
int	isNullable(int column) Can you put a NULL in this column?
boolean	isReadOnly(int column) Is a column definitely not writable?
boolean	isSearchable(int column) Can the column be used in a WHERE clause?
boolean	isSigned(int column) Is the column a signed number?
boolean	isWrapperFor(java.lang.Class<?> iface)
boolean	isWritable(int column) Is it possible for a write on the column to succeed?
<T> T	unwrap(java.lang.Class<T> iface)

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.sql.ResultSetMetaData

getColumnCount, getColumnType

Constructor Detail

VTIMetaDataTemplate

public VTIMetaDataTemplate()

Method Detail

isWrapperFor

public boolean isWrapperFor(java.lang.Class<?> iface)
                     throws java.sql.SQLException

Specified by:

isWrapperFor in interface java.sql.Wrapper

Throws:

java.sql.SQLException

unwrap

public <T> T unwrap(java.lang.Class<T> iface)
             throws java.sql.SQLException

Specified by:

unwrap in interface java.sql.Wrapper

Throws:

java.sql.SQLException

isAutoIncrement

public boolean isAutoIncrement(int column)
                        throws java.sql.SQLException

Is the column automatically numbered, and thus read-only?

Specified by:

isAutoIncrement in interface java.sql.ResultSetMetaData

Parameters:

column - the first column is 1, the second is 2, ...

Returns:

true if the column is automatically numbered

Throws:

java.sql.SQLException - if a database-access error occurs.

isCaseSensitive

public boolean isCaseSensitive(int column)
                        throws java.sql.SQLException

Does a column's case matter?

Specified by:

isCaseSensitive in interface java.sql.ResultSetMetaData

Parameters:

column - the first column is 1, the second is 2, ...

Returns:

true if the column is case-sensitive

Throws:

java.sql.SQLException - if a database-access error occurs.

isSearchable

public boolean isSearchable(int column)
                     throws java.sql.SQLException

Can the column be used in a WHERE clause?

Specified by:

isSearchable in interface java.sql.ResultSetMetaData

Parameters:

column - the first column is 1, the second is 2, ...

Returns:

true if the column is searchable

Throws:

java.sql.SQLException - if a database-access error occurs.

isCurrency

public boolean isCurrency(int column)
                   throws java.sql.SQLException

Is the column a cash value?

Specified by:

isCurrency in interface java.sql.ResultSetMetaData

Parameters:

column - the first column is 1, the second is 2, ...

Returns:

true if the column is a cash value

Throws:

java.sql.SQLException - if a database-access error occurs.

isNullable

public int isNullable(int column)
               throws java.sql.SQLException

Can you put a NULL in this column?

Specified by:

isNullable in interface java.sql.ResultSetMetaData

Parameters:

column - the first column is 1, the second is 2, ...

Returns:

columnNoNulls, columnNullable or columnNullableUnknown

Throws:

java.sql.SQLException - if a database-access error occurs.

isSigned

public boolean isSigned(int column)
                 throws java.sql.SQLException

Is the column a signed number?

Specified by:

isSigned in interface java.sql.ResultSetMetaData

Parameters:

column - the first column is 1, the second is 2, ...

Returns:

true if the column is a signed number

Throws:

java.sql.SQLException - if a database-access error occurs.

getColumnDisplaySize

public int getColumnDisplaySize(int column)
                         throws java.sql.SQLException

What's the column's normal maximum width in chars?

Specified by:

getColumnDisplaySize in interface java.sql.ResultSetMetaData

Parameters:

column - the first column is 1, the second is 2, ...

Returns:

the column's maximum width

Throws:

java.sql.SQLException - if a database-access error occurs.

getColumnLabel

public java.lang.String getColumnLabel(int column)
                                throws java.sql.SQLException

What's the suggested column title for use in printouts and displays?

Specified by:

getColumnLabel in interface java.sql.ResultSetMetaData

Parameters:

column - the first column is 1, the second is 2, ...

Returns:

the column's title

Throws:

java.sql.SQLException - if a database-access error occurs.

getColumnName

public java.lang.String getColumnName(int column)
                               throws java.sql.SQLException

What's a column's name?

Specified by:

getColumnName in interface java.sql.ResultSetMetaData

Parameters:

column - the first column is 1, the second is 2, ...

Returns:

column name

Throws:

java.sql.SQLException - if a database-access error occurs.

getSchemaName

public java.lang.String getSchemaName(int column)
                               throws java.sql.SQLException

What's a column's table's schema?

Specified by:

getSchemaName in interface java.sql.ResultSetMetaData

Parameters:

column - the first column is 1, the second is 2, ...

Returns:

schema name or "" if not applicable

Throws:

java.sql.SQLException - if a database-access error occurs.

getPrecision

public int getPrecision(int column)
                 throws java.sql.SQLException

How many decimal digits are in the column?

Specified by:

getPrecision in interface java.sql.ResultSetMetaData

Parameters:

column - the first column is 1, the second is 2, ...

Returns:

the column's precision

Throws:

java.sql.SQLException - if a database-access error occurs.

getScale

public int getScale(int column)
             throws java.sql.SQLException

What's a column's number of digits to the right of the decimal point?

Specified by:

getScale in interface java.sql.ResultSetMetaData

Parameters:

column - the first column is 1, the second is 2, ...

Returns:

the column's scale

Throws:

java.sql.SQLException - if a database-access error occurs.

getTableName

public java.lang.String getTableName(int column)
                              throws java.sql.SQLException

What's a column's table name?

Specified by:

getTableName in interface java.sql.ResultSetMetaData

Parameters:

column - the first column is 1, the second is 2, ...

Returns:

the column's table name or "" if not applicable

Throws:

java.sql.SQLException - if a database-access error occurs.

getCatalogName

public java.lang.String getCatalogName(int column)
                                throws java.sql.SQLException

What's a column's table's catalog name?

Specified by:

getCatalogName in interface java.sql.ResultSetMetaData

Parameters:

column - the first column is 1, the second is 2, ...

Returns:

the column's table's catalog name or "" if not applicable.

Throws:

java.sql.SQLException - if a database-access error occurs.

getColumnTypeName

public java.lang.String getColumnTypeName(int column)
                                   throws java.sql.SQLException

What's a column's data source specific type name?

Specified by:

getColumnTypeName in interface java.sql.ResultSetMetaData

Parameters:

column - the first column is 1, the second is 2, ...

Returns:

the column's type name

Throws:

java.sql.SQLException - if a database-access error occurs.

isReadOnly

public boolean isReadOnly(int column)
                   throws java.sql.SQLException

Is a column definitely not writable?

Specified by:

isReadOnly in interface java.sql.ResultSetMetaData

Parameters:

column - the first column is 1, the second is 2, ...

Returns:

true - vti's are read only false - column is not read-only

Throws:

java.sql.SQLException - if a database-access error occurs.

isWritable

public boolean isWritable(int column)
                   throws java.sql.SQLException

Is it possible for a write on the column to succeed?

Specified by:

isWritable in interface java.sql.ResultSetMetaData

Parameters:

column - the first column is 1, the second is 2, ...

Returns:

true if column is possibly writable

Throws:

java.sql.SQLException - if a database-access error occurs.

isDefinitelyWritable

public boolean isDefinitelyWritable(int column)
                             throws java.sql.SQLException

Will a write on the column definitely succeed?

Specified by:

isDefinitelyWritable in interface java.sql.ResultSetMetaData

Parameters:

column - the first column is 1, the second is 2, ...

Returns:

true if column is definitely writable

Throws:

java.sql.SQLException - if a database-access error occurs.

getColumnClassName

public java.lang.String getColumnClassName(int column)
                                    throws java.sql.SQLException

Returns the fully-qualified name of the Java class whose instances are manufactured if the method ResultSet.getObject is called to retrieve a value from the column. JDBC 2.0.

Specified by:

getColumnClassName in interface java.sql.ResultSetMetaData

Throws:

java.sql.SQLException - if a database-access error occurs