Java(TM) 2 Platform, Standard Edition, v1.2.2 API Specification: Interface ResultSetMetaData - JDK 5 Documentation v1.2.2, Java 2 SDK 英文文档

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java.sql
Interface ResultSetMetaData

public interface ResultSetMetaData

An object that can be used to find out about the types and properties of the columns in a ResultSet.

Field Summary

static int columnNoNulls
          Column does not allow NULL values.

static int columnNullable
          Column allows NULL values.

static int columnNullableUnknown
          Nullability of column values is unknown.

Method Summary

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

String getColumnClassName(int column)
          JDBC 2.0

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

int getColumnDisplaySize(int column)
          Indicates the column's normal max width in chars.

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

String getColumnName(int column)
          Gets a column's name.

int getColumnType(int column)
          Retrieves a column's SQL type.

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

int getPrecision(int column)
          Gets a column's number of decimal digits.

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

String getSchemaName(int column)
          Gets a column's table's schema.

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

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

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

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

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

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

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

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

Field Detail

columnNoNulls

public static final int columnNoNulls

Column does not allow NULL values.

columnNullable

public static final int columnNullable

Column allows NULL values.

columnNullableUnknown

public static final int columnNullableUnknown

Nullability of column values is unknown.

Method Detail

getColumnCount

public int getColumnCount()
                   throws SQLException

Returns the number of columns in this ResultSet.

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

isAutoIncrement

public boolean isAutoIncrement(int column)
                        throws SQLException

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

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

isCaseSensitive

public 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
Throws:: SQLException - if a database access error occurs

isSearchable

public boolean isSearchable(int column)
                     throws SQLException

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

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

isCurrency

public boolean isCurrency(int column)
                   throws SQLException

Indicates whether the column is a cash value.

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

isNullable

public 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

public boolean isSigned(int column)
                 throws SQLException

Indicates whether values in the column are signed numbers.

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

getColumnDisplaySize

public int getColumnDisplaySize(int column)
                         throws SQLException

Indicates the column's normal max width in chars.

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

public String getColumnLabel(int column)
                      throws SQLException

Gets the suggested column 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

public String getColumnName(int column)
                     throws SQLException

Gets a 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

public String getSchemaName(int column)
                     throws SQLException

Gets a 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

public int getPrecision(int column)
                 throws SQLException

Gets a 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

public int getScale(int column)
             throws SQLException

Gets a 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

public String getTableName(int column)
                    throws SQLException

Gets a 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

public String getCatalogName(int column)
                      throws SQLException

Gets a column's table's catalog name.

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

getColumnType

public int getColumnType(int column)
                  throws SQLException

Retrieves a 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

public String getColumnTypeName(int column)
                         throws SQLException

Retrieves a 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

public boolean isReadOnly(int column)
                   throws SQLException

Indicates whether a column is definitely not writable.

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

isWritable

public boolean isWritable(int column)
                   throws SQLException

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

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

isDefinitelyWritable

public boolean isDefinitelyWritable(int column)
                             throws SQLException

Indicates whether a write on the column will definitely succeed.

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

getColumnClassName

public String getColumnClassName(int column)
                          throws SQLException

JDBC 2.0

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.

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