com.mysql.jdbc
Class ResultSetMetaData

java.lang.Object
  com.mysql.jdbc.ResultSetMetaData

All Implemented Interfaces:

java.sql.ResultSetMetaData, java.sql.Wrapper

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

A ResultSetMetaData object can be used to find out about the types and properties of the columns in a ResultSet

Version:

$Id: ResultSetMetaData.java,v 1.1.2.1 2005/05/13 18:58:38 mmatthews Exp $

Author:

Mark Matthews

See Also:

ResultSetMetaData

Field Summary

Fields inherited from interface java.sql.ResultSetMetaData

columnNoNulls, columnNullable, columnNullableUnknown

Constructor Summary

ResultSetMetaData(Field[] fields, boolean useOldAliasBehavior)
Initialise for a result with a tuple set and a field descriptor set

Method Summary

java.lang.String	getCatalogName(int column) What's a column's table's catalog name?
java.lang.String	getColumnCharacterEncoding(int column) What's the Java character encoding name for the given column?
java.lang.String	getColumnCharacterSet(int column) What's the MySQL character set name for the given column?
java.lang.String	getColumnClassName(int column) JDBC 2.0
int	getColumnCount() Whats the number of columns in the ResultSet?
int	getColumnDisplaySize(int column) What is the column's normal maximum width in characters?
java.lang.String	getColumnLabel(int column) What is the suggested column title for use in printouts and displays?
java.lang.String	getColumnName(int column) What's a column's name?
int	getColumnType(int column) What is a column's SQL Type? (java.sql.Type int)
java.lang.String	getColumnTypeName(int column) Whats is the column's data source specific type name?
protected Field	getField(int columnIndex) Returns the field instance for the given column index
int	getPrecision(int column) What is a column's number of decimal digits.
int	getScale(int column) What is a column's number of digits to the right of the decimal point?
java.lang.String	getSchemaName(int column) What is a column's table's schema? This relies on us knowing the table name.
java.lang.String	getTableName(int column) Whats a column's table's 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 this column definately succeed?
int	isNullable(int column) Can you put a NULL in this column?
boolean	isReadOnly(int column) Is the column definitely not writable?
boolean	isSearchable(int column) Can the column be used in a WHERE clause? Basically for this, I split the functions into two types: recognised types (which are always useable), and OTHER types (which may or may not be useable).
boolean	isSigned(int column) Is the column a signed number?
boolean	isWrapperFor(java.lang.Class iface) Returns true if this either implements the interface argument or is directly or indirectly a wrapper for an object that does.
boolean	isWritable(int column) Is it possible for a write on the column to succeed?
java.lang.String	toString() Returns a string representation of this object
java.lang.Object	unwrap(java.lang.Class iface) Returns an object that implements the given interface to allow access to non-standard methods, or standard methods not exposed by the proxy.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

ResultSetMetaData

public ResultSetMetaData(Field[] fields,
                         boolean useOldAliasBehavior)

Initialise for a result with a tuple set and a field descriptor set

Parameters:

fields - the array of field descriptors

Method Detail

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:

catalog name, or "" if not applicable

Throws:

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

getColumnCharacterEncoding

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

What's the Java character encoding name for the given column?

Parameters:

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

Returns:

the Java character encoding name for the given column, or null if no Java character encoding maps to the MySQL character set for the given column.

Throws:

java.sql.SQLException - if an invalid column index is given.

getColumnCharacterSet

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

What's the MySQL character set name for the given column?

Parameters:

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

Returns:

the MySQL character set name for the given column

Throws:

java.sql.SQLException - if an invalid column index is given.

getColumnClassName

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

JDBC 2.0

Return the fully qualified name of the Java class whose instances are manufactured if ResultSet.getObject() is called to retrieve a value from the column. ResultSet.getObject() may return a subClass of the class returned by this method.

Specified by:

getColumnClassName in interface java.sql.ResultSetMetaData

Parameters:

column - the column number to retrieve information for

Returns:

the fully qualified name of the Java class whose instances are manufactured if ResultSet.getObject() is called to retrieve a value from the column.

Throws:

java.sql.SQLException - if an error occurs

getColumnCount

public int getColumnCount()
                   throws java.sql.SQLException

Whats the number of columns in the ResultSet?

Specified by:

getColumnCount in interface java.sql.ResultSetMetaData

Returns:

the number

Throws:

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

getColumnDisplaySize

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

What is the column's normal maximum width in characters?

Specified by:

getColumnDisplaySize in interface java.sql.ResultSetMetaData

Parameters:

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

Returns:

the 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 is 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, etc.

Returns:

the column label

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, etc.

Returns:

the column name

Throws:

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

getColumnType

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

What is a column's SQL Type? (java.sql.Type int)

Specified by:

getColumnType in interface java.sql.ResultSetMetaData

Parameters:

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

Returns:

the java.sql.Type value

Throws:

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

See Also:

Types

getColumnTypeName

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

Whats is the 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, etc.

Returns:

the type name

Throws:

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

getField

protected Field getField(int columnIndex)
                  throws java.sql.SQLException

Returns the field instance for the given column index

Parameters:

columnIndex - the column number to retrieve a field instance for

Returns:

the field instance for the given column index

Throws:

java.sql.SQLException - if an error occurs

getPrecision

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

What is a column's number of decimal digits.

Specified by:

getPrecision in interface java.sql.ResultSetMetaData

Parameters:

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

Returns:

the precision

Throws:

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

getScale

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

What is 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 scale

Throws:

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

getSchemaName

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

What is a column's table's schema? This relies on us knowing the table name. The JDBC specification allows us to return "" if this is not applicable.

Specified by:

getSchemaName in interface java.sql.ResultSetMetaData

Parameters:

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

Returns:

the Schema

Throws:

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

getTableName

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

Whats a column's table's name?

Specified by:

getTableName in interface java.sql.ResultSetMetaData

Parameters:

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

Returns:

column name, or "" if not applicable

Throws:

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

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 so

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 so

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 its a cash column

Throws:

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

isDefinitelyWritable

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

Will a write on this column definately succeed?

Specified by:

isDefinitelyWritable in interface java.sql.ResultSetMetaData

Parameters:

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

Returns:

true if so

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:

one of the columnNullable values

Throws:

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

isReadOnly

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

Is the column definitely not writable?

Specified by:

isReadOnly in interface java.sql.ResultSetMetaData

Parameters:

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

Returns:

true if so

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? Basically for this, I split the functions into two types: recognised types (which are always useable), and OTHER types (which may or may not be useable). The OTHER types, for now, I will assume they are useable. We should really query the catalog to see if they are useable.

Specified by:

isSearchable in interface java.sql.ResultSetMetaData

Parameters:

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

Returns:

true if they can be used in a WHERE clause

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 so

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, etc.

Returns:

true if so

Throws:

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

toString

public java.lang.String toString()

Returns a string representation of this object

Overrides:

toString in class java.lang.Object

Returns:

...

isWrapperFor

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

Returns true if this either implements the interface argument or is directly or indirectly a wrapper for an object that does. Returns false otherwise. If this implements the interface then return true, else if this is a wrapper then return the result of recursively calling isWrapperFor on the wrapped object. If this does not implement the interface and is not a wrapper, return false. This method should be implemented as a low-cost operation compared to unwrap so that callers can use this method to avoid expensive unwrap calls that may fail. If this method returns true then calling unwrap with the same argument should succeed.

Specified by:

isWrapperFor in interface java.sql.Wrapper

Parameters:

interfaces - a Class defining an interface.

Returns:

true if this implements the interface or directly or indirectly wraps an object that does.

Throws:

java.sql.SQLException - if an error occurs while determining whether this is a wrapper for an object with the given interface.

Since:

1.6

unwrap

public java.lang.Object unwrap(java.lang.Class iface)
                        throws java.sql.SQLException

Returns an object that implements the given interface to allow access to non-standard methods, or standard methods not exposed by the proxy. The result may be either the object found to implement the interface or a proxy for that object. If the receiver implements the interface then that is the object. If the receiver is a wrapper and the wrapped object implements the interface then that is the object. Otherwise the object is the result of calling unwrap recursively on the wrapped object. If the receiver is not a wrapper and does not implement the interface, then an SQLException is thrown.

Specified by:

unwrap in interface java.sql.Wrapper

Parameters:

iface - A Class defining an interface that the result must implement.

Returns:

an object that implements the interface. May be a proxy for the actual implementing object.

Throws:

java.sql.SQLException - If no object found that implements the interface

Since:

1.6