ResultSetMetaData (Java 2 Platform SE 5.0) - JDK 5 Documentation v1.5.0, Java 2 SDK 英文文档

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Standard Ed. 5.0

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java.sql
Interface ResultSetMetaData

All Known Subinterfaces:: RowSetMetaData

All Known Implementing Classes:: RowSetMetaDataImpl

public interface ResultSetMetaData

An object that can be used to get information about the types and properties of the columns in a ResultSet object. The following code fragment creates the ResultSet object rs, creates the ResultSetMetaData object rsmd, and uses rsmd to find out how many columns rs has and whether the first column in rs can be used in a WHERE clause.


     ResultSet rs = stmt.executeQuery("SELECT a, b, c FROM TABLE2");
     ResultSetMetaData rsmd = rs.getMetaData();
     int numberOfColumns = rsmd.getColumnCount();
     boolean b = rsmd.isSearchable(1);

Field Summary

static int columnNoNulls
          The constant indicating that a column does not allow NULL values.

static int columnNullable
          The constant indicating that a column allows NULL values.

static int columnNullableUnknown
          The constant indicating that the nullability of a column's values is unknown.

Method Summary

String getCatalogName(int column)
          Gets the designated column's table's catalog name.

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 getColumnCount()
          Returns the number of columns in this ResultSet object.

int getColumnDisplaySize(int column)
          Indicates the designated column's normal maximum width in characters.

String getColumnLabel(int column)
          Gets the designated column's suggested title for use in printouts and displays.

String getColumnName(int column)
          Get the designated column's name.

int getColumnType(int column)
          Retrieves the designated column's SQL type.

String getColumnTypeName(int column)
          Retrieves the designated column's database-specific type name.

int getPrecision(int column)
          Get the designated column's number of decimal digits.

int getScale(int column)
          Gets the designated column's number of digits to right of the decimal point.

String getSchemaName(int column)
          Get the designated column's table's schema.

String getTableName(int column)
          Gets the designated column's table name.

boolean isAutoIncrement(int column)
          Indicates whether the designated column is automatically numbered, thus read-only.

boolean isCaseSensitive(int column)
          Indicates whether a column's case matters.

boolean isCurrency(int column)
          Indicates whether the designated column is a cash value.

boolean isDefinitelyWritable(int column)
          Indicates whether a write on the designated column will definitely succeed.

int isNullable(int column)
          Indicates the nullability of values in the designated column.

boolean isReadOnly(int column)
          Indicates whether the designated column is definitely not writable.

boolean isSearchable(int column)
          Indicates whether the designated column can be used in a where clause.

boolean isSigned(int column)
          Indicates whether values in the designated column are signed numbers.

boolean isWritable(int column)
          Indicates whether it is possible for a write on the designated column to succeed.

Field Summary
`static int`	`columnNoNulls` The constant indicating that a column does not allow `NULL` values.
`static int`	`columnNullable` The constant indicating that a column allows `NULL` values.
`static int`	`columnNullableUnknown` The constant indicating that the nullability of a column's values is unknown.

Method Summary
`String`	`getCatalogName(int column)` Gets the designated column's table's catalog name.
`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`	`getColumnCount()` Returns the number of columns in this `ResultSet` object.
`int`	`getColumnDisplaySize(int column)` Indicates the designated column's normal maximum width in characters.
`String`	`getColumnLabel(int column)` Gets the designated column's suggested title for use in printouts and displays.
`String`	`getColumnName(int column)` Get the designated column's name.
`int`	`getColumnType(int column)` Retrieves the designated column's SQL type.
`String`	`getColumnTypeName(int column)` Retrieves the designated column's database-specific type name.
`int`	`getPrecision(int column)` Get the designated column's number of decimal digits.
`int`	`getScale(int column)` Gets the designated column's number of digits to right of the decimal point.
`String`	`getSchemaName(int column)` Get the designated column's table's schema.
`String`	`getTableName(int column)` Gets the designated column's table name.
`boolean`	`isAutoIncrement(int column)` Indicates whether the designated column is automatically numbered, thus read-only.
`boolean`	`isCaseSensitive(int column)` Indicates whether a column's case matters.
`boolean`	`isCurrency(int column)` Indicates whether the designated column is a cash value.
`boolean`	`isDefinitelyWritable(int column)` Indicates whether a write on the designated column will definitely succeed.
`int`	`isNullable(int column)` Indicates the nullability of values in the designated column.
`boolean`	`isReadOnly(int column)` Indicates whether the designated column is definitely not writable.
`boolean`	`isSearchable(int column)` Indicates whether the designated column can be used in a where clause.
`boolean`	`isSigned(int column)` Indicates whether values in the designated column are signed numbers.
`boolean`	`isWritable(int column)` Indicates whether it is possible for a write on the designated column to succeed.

Field Detail

columnNoNulls

static final int columnNoNulls

The constant indicating that a column does not allow NULL values.

See Also:: Constant Field Values

columnNullable

static final int columnNullable

The constant indicating that a column allows NULL values.

See Also:: Constant Field Values

columnNullableUnknown

static final int columnNullableUnknown

The constant indicating that the nullability of a column's values is unknown.

See Also:: Constant Field Values

Method Detail

getColumnCount

int getColumnCount()
                   throws SQLException

Returns the number of columns in this ResultSet object.

Returns:: the number of columns
Throws:: SQLException - if a database access error occurs

isAutoIncrement

boolean isAutoIncrement(int column)
                        throws SQLException

Indicates whether the designated column is automatically numbered, thus read-only.

Parameters:: column - the first column is 1, the second is 2, ...
Returns:: true if so; false otherwise
Throws:: SQLException - if a database access error occurs

isCaseSensitive

boolean isCaseSensitive(int column)
                        throws SQLException

Indicates whether a column's case matters.

Parameters:: column - the first column is 1, the second is 2, ...
Returns:: true if so; false otherwise
Throws:: SQLException - if a database access error occurs

isSearchable

boolean isSearchable(int column)
                     throws SQLException

Indicates whether the designated column can be used in a where clause.

Parameters:: column - the first column is 1, the second is 2, ...
Returns:: true if so; false otherwise
Throws:: SQLException - if a database access error occurs

isCurrency

boolean isCurrency(int column)
                   throws SQLException

Indicates whether the designated column is a cash value.

Parameters:: column - the first column is 1, the second is 2, ...
Returns:: true if so; false otherwise
Throws:: SQLException - if a database access error occurs

isNullable

int isNullable(int column)
               throws SQLException

Indicates the nullability of values in the designated column.

Parameters:: column - the first column is 1, the second is 2, ...
Returns:: the nullability status of the given column; one of columnNoNulls, columnNullable or columnNullableUnknown
Throws:: SQLException - if a database access error occurs

isSigned

boolean isSigned(int column)
                 throws SQLException

Indicates whether values in the designated column are signed numbers.

Parameters:: column - the first column is 1, the second is 2, ...
Returns:: true if so; false otherwise
Throws:: SQLException - if a database access error occurs

getColumnDisplaySize

int getColumnDisplaySize(int column)
                         throws SQLException

Indicates the designated column's normal maximum width in characters.

Parameters:: column - the first column is 1, the second is 2, ...
Returns:: the normal maximum number of characters allowed as the width of the designated column
Throws:: SQLException - if a database access error occurs

getColumnLabel

String getColumnLabel(int column)
                      throws SQLException

Gets the designated column's suggested title for use in printouts and displays.

Parameters:: column - the first column is 1, the second is 2, ...
Returns:: the suggested column title
Throws:: SQLException - if a database access error occurs

getColumnName

String getColumnName(int column)
                     throws SQLException

Get the designated column's name.

Parameters:: column - the first column is 1, the second is 2, ...
Returns:: column name
Throws:: SQLException - if a database access error occurs

getSchemaName

String getSchemaName(int column)
                     throws SQLException

Get the designated column's table's schema.

Parameters:: column - the first column is 1, the second is 2, ...
Returns:: schema name or "" if not applicable
Throws:: SQLException - if a database access error occurs

getPrecision

int getPrecision(int column)
                 throws SQLException

Get the designated column's number of decimal digits.

Parameters:: column - the first column is 1, the second is 2, ...
Returns:: precision
Throws:: SQLException - if a database access error occurs

getScale

int getScale(int column)
             throws SQLException

Gets the designated column's number of digits to right of the decimal point.

Parameters:: column - the first column is 1, the second is 2, ...
Returns:: scale
Throws:: SQLException - if a database access error occurs

getTableName

String getTableName(int column)
                    throws SQLException

Gets the designated column's table name.

Parameters:: column - the first column is 1, the second is 2, ...
Returns:: table name or "" if not applicable
Throws:: SQLException - if a database access error occurs

getCatalogName

String getCatalogName(int column)
                      throws SQLException

Gets the designated column's table's catalog name.

Parameters:: column - the first column is 1, the second is 2, ...
Returns:: the name of the catalog for the table in which the given column appears or "" if not applicable
Throws:: SQLException - if a database access error occurs

getColumnType

int getColumnType(int column)
                  throws SQLException

Retrieves the designated column's SQL type.

Parameters:: column - the first column is 1, the second is 2, ...
Returns:: SQL type from java.sql.Types
Throws:: SQLException - if a database access error occurs
See Also:: Types

getColumnTypeName

String getColumnTypeName(int column)
                         throws SQLException

Retrieves the designated column's database-specific type name.

Parameters:: column - the first column is 1, the second is 2, ...
Returns:: type name used by the database. If the column type is a user-defined type, then a fully-qualified type name is returned.
Throws:: SQLException - if a database access error occurs

isReadOnly

boolean isReadOnly(int column)
                   throws SQLException

Indicates whether the designated column is definitely not writable.

Parameters:: column - the first column is 1, the second is 2, ...
Returns:: true if so; false otherwise
Throws:: SQLException - if a database access error occurs

isWritable

boolean isWritable(int column)
                   throws SQLException

Indicates whether it is possible for a write on the designated column to succeed.

Parameters:: column - the first column is 1, the second is 2, ...
Returns:: true if so; false otherwise
Throws:: SQLException - if a database access error occurs

isDefinitelyWritable

boolean isDefinitelyWritable(int column)
                             throws SQLException

Indicates whether a write on the designated column will definitely succeed.

Parameters:: column - the first column is 1, the second is 2, ...
Returns:: true if so; false otherwise
Throws:: SQLException - if a database access error occurs

getColumnClassName

String getColumnClassName(int column)
                          throws 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. ResultSet.getObject may return a subclass of the class returned by this method.

Parameters:: column - the first column is 1, the second is 2, ...
Returns:: the fully-qualified name of the class in the Java programming language that would be used by the method ResultSet.getObject to retrieve the value in the specified column. This is the class name used for custom mapping.
Throws:: SQLException - if a database access error occurs
Since:: 1.2