net.sourceforge.jtds.jdbc
Class TdsData

java.lang.Object
  net.sourceforge.jtds.jdbc.TdsData

public class TdsData

extends java.lang.Object

Implement TDS data types and related I/O logic.

Implementation notes:

This class encapsulates all the knowledge about reading and writing TDS data descriptors and related application data.

There are four key methods supplied here:

1. readType() - Reads the column and parameter meta data.
2. readData() - Reads actual data values.
3. writeParam() - Write parameter descriptors and data.
4. getNativeType() - knows how to map JDBC data types to the equivalent TDS type.

Version:

$Id: TdsData.java,v 1.60.2.3 2009-11-05 10:42:18 ickzon Exp $

Author:

Mike Hutchinson, Alin Sinpalean, freeTDS project

Nested Class Summary

private static class

TdsData.TypeInfo This class implements a descriptor for TDS data types;

Field Summary

(package private) static int	DEFAULT_PRECISION_28 Default precision for SQL Server 6.5 and 7.
(package private) static int	DEFAULT_PRECISION_38 Default precision for Sybase and SQL Server 2000 and newer.
(package private) static int	DEFAULT_SCALE Default Decimal Scale.
private static int	MS_LONGVAR_MAX
private static int	SYB_CHUNK_SIZE
private static int	SYB_LONGVAR_MAX
private static int	SYBBINARY
private static int	SYBBIT
private static int	SYBBITN
private static int	SYBCHAR
private static int	SYBDATE
private static int	SYBDATEN
private static int	SYBDATETIME
private static int	SYBDATETIME4
private static int	SYBDATETIMN
private static int	SYBDECIMAL
private static int	SYBFLT8
private static int	SYBFLTN
private static int	SYBIMAGE
private static int	SYBINT1
private static int	SYBINT2
private static int	SYBINT4
private static int	SYBINT8
private static int	SYBINTN
private static int	SYBLONGBINARY
(package private) static int	SYBLONGDATA
private static int	SYBMONEY
private static int	SYBMONEY4
private static int	SYBMONEYN
private static int	SYBNTEXT
private static int	SYBNUMERIC
private static int	SYBNVARCHAR
private static int	SYBREAL
private static int	SYBSINT1
private static int	SYBSINT8
private static int	SYBTEXT
private static int	SYBTIME
private static int	SYBTIMEN
private static int	SYBUINT2
private static int	SYBUINT4
private static int	SYBUINT8
private static int	SYBUINTN
private static int	SYBUNIQUE
private static int	SYBUNITEXT
private static int	SYBVARBINARY
private static int	SYBVARCHAR
private static int	SYBVARIANT
private static int	SYBVOID
private static TdsData.TypeInfo[]	types Array of TDS data type descriptors.
private static int	UDT_BINARY
private static int	UDT_CHAR
private static int	UDT_LONGSYSNAME
private static int	UDT_NCHAR
private static int	UDT_NEWSYSNAME
private static int	UDT_NVARCHAR
private static int	UDT_SYSNAME
private static int	UDT_TIMESTAMP
private static int	UDT_UNICHAR
private static int	UDT_UNITEXT
private static int	UDT_UNIVARCHAR
private static int	UDT_VARBINARY
private static int	UDT_VARCHAR
private static int	VAR_MAX
private static int	XSYBBINARY
private static int	XSYBCHAR
private static int	XSYBNCHAR
private static int	XSYBNVARCHAR
private static int	XSYBVARBINARY
private static int	XSYBVARCHAR

Constructor Summary

private

TdsData() Private constructor to prevent users creating an actual instance of this class.

Method Summary

private static boolean	canEncode(java.lang.String value, java.lang.String charset) Establish if a String can be converted to a byte based character set.
(package private) static void	fillInType(ColInfo ci) Fill in the TDS native type code and all other fields for a ColInfo instance with the JDBC type set.
(package private) static int	getCollation(ResponseStream in, ColInfo ci) TDS 8 supplies collation information for character data types.
private static java.lang.Object	getDatetimeValue(ResponseStream in, int type) Get a DATETIME value from the server response stream.
private static java.lang.Object	getMoneyValue(ResponseStream in, int type) Read a MONEY value from the server response stream.
static java.lang.String	getMSTypeName(java.lang.String typeName, int tdsType) For SQL 2005 This routine will modify the meta data to allow the caller to distinguish between varchar(max) and text or varbinary(max) and image or nvarchar(max) and ntext.
(package private) static void	getNativeType(ConnectionJDBC2 connection, ParamInfo pi) Retrieve the TDS native type code for the parameter.
(package private) static int	getTds5ParamSize(java.lang.String charset, boolean isWideChar, ParamInfo pi, boolean useParamNames) Calculate the size of the parameter descriptor array for TDS 5 packets.
static int	getTdsVersion(int rawTdsVersion) Extract the TDS protocol version from the value returned by the server in the LOGINACK packet.
private static java.lang.Object	getVariant(ConnectionJDBC2 connection, ResponseStream in) Read a MSQL 2000 sql_variant data value from the input stream.
(package private) static boolean	isCollation(ColInfo ci) Retrieve the collation status of the column.
(package private) static boolean	isCurrency(ColInfo ci) Retrieve the currency status of the column.
(package private) static boolean	isSearchable(ColInfo ci) Retrieve the searchable status of the column.
(package private) static boolean	isSigned(ColInfo ci) Retrieve the signed status of the column.
(package private) static boolean	isUnicode(ColInfo ci) Determines whether the column is Unicode encoded.
(package private) static void	putCollation(RequestStream out, ParamInfo pi) TDS 8 requires collation information for char data descriptors.
private static void	putDateTimeValue(RequestStream out, DateTime value) Output a java.sql.Date/Time/Timestamp value to the server as a Sybase datetime value.
(package private) static java.lang.Object	readData(ConnectionJDBC2 connection, ResponseStream in, ColInfo ci) Read the TDS data item from the Response Stream.
(package private) static int	readType(ResponseStream in, ColInfo ci) Read the TDS datastream and populate the ColInfo parameter with data type and related information.
(package private) static void	setColumnCharset(ColInfo ci, ConnectionJDBC2 connection) Set the charsetInfo field of ci according to the value of its collation field.
(package private) static void	writeParam(RequestStream out, CharsetInfo charsetInfo, byte[] collation, ParamInfo pi) Write a parameter to the server request stream.
(package private) static void	writeTds5Param(RequestStream out, CharsetInfo charsetInfo, ParamInfo pi) Write the actual TDS 5 parameter data.
(package private) static void	writeTds5ParamFmt(RequestStream out, java.lang.String charset, boolean isWideChar, ParamInfo pi, boolean useParamNames) Write a TDS 5 parameter format descriptor.

Methods inherited from class java.lang.Object

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

Field Detail

SYBCHAR

private static final int SYBCHAR

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Constant Field Values

SYBVARCHAR

private static final int SYBVARCHAR

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Constant Field Values

SYBINTN

private static final int SYBINTN

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SYBINT1

private static final int SYBINT1

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SYBDATE

private static final int SYBDATE

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SYBTIME

private static final int SYBTIME

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SYBINT2

private static final int SYBINT2

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SYBINT4

private static final int SYBINT4

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SYBINT8

private static final int SYBINT8

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SYBFLT8

private static final int SYBFLT8

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SYBDATETIME

private static final int SYBDATETIME

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SYBBIT

private static final int SYBBIT

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SYBTEXT

private static final int SYBTEXT

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SYBNTEXT

private static final int SYBNTEXT

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SYBIMAGE

private static final int SYBIMAGE

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SYBMONEY4

private static final int SYBMONEY4

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SYBMONEY

private static final int SYBMONEY

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SYBDATETIME4

private static final int SYBDATETIME4

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SYBREAL

private static final int SYBREAL

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SYBBINARY

private static final int SYBBINARY

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SYBVOID

private static final int SYBVOID

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SYBVARBINARY

private static final int SYBVARBINARY

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SYBNVARCHAR

private static final int SYBNVARCHAR

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SYBBITN

private static final int SYBBITN

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SYBNUMERIC

private static final int SYBNUMERIC

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SYBDECIMAL

private static final int SYBDECIMAL

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SYBFLTN

private static final int SYBFLTN

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SYBMONEYN

private static final int SYBMONEYN

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SYBDATETIMN

private static final int SYBDATETIMN

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SYBDATEN

private static final int SYBDATEN

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SYBTIMEN

private static final int SYBTIMEN

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XSYBCHAR

private static final int XSYBCHAR

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XSYBVARCHAR

private static final int XSYBVARCHAR

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XSYBNVARCHAR

private static final int XSYBNVARCHAR

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XSYBNCHAR

private static final int XSYBNCHAR

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XSYBVARBINARY

private static final int XSYBVARBINARY

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XSYBBINARY

private static final int XSYBBINARY

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SYBUNITEXT

private static final int SYBUNITEXT

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SYBLONGBINARY

private static final int SYBLONGBINARY

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SYBSINT1

private static final int SYBSINT1

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SYBUINT2

private static final int SYBUINT2

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SYBUINT4

private static final int SYBUINT4

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SYBUINT8

private static final int SYBUINT8

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SYBUINTN

private static final int SYBUINTN

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SYBUNIQUE

private static final int SYBUNIQUE

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SYBVARIANT

private static final int SYBVARIANT

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SYBSINT8

private static final int SYBSINT8

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SYBLONGDATA

static final int SYBLONGDATA

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UDT_CHAR

private static final int UDT_CHAR

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UDT_VARCHAR

private static final int UDT_VARCHAR

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UDT_BINARY

private static final int UDT_BINARY

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UDT_VARBINARY

private static final int UDT_VARBINARY

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UDT_SYSNAME

private static final int UDT_SYSNAME

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UDT_NCHAR

private static final int UDT_NCHAR

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UDT_NVARCHAR

private static final int UDT_NVARCHAR

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UDT_UNICHAR

private static final int UDT_UNICHAR

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UDT_UNIVARCHAR

private static final int UDT_UNIVARCHAR

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UDT_UNITEXT

private static final int UDT_UNITEXT

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UDT_LONGSYSNAME

private static final int UDT_LONGSYSNAME

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UDT_TIMESTAMP

private static final int UDT_TIMESTAMP

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UDT_NEWSYSNAME

private static final int UDT_NEWSYSNAME

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VAR_MAX

private static final int VAR_MAX

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SYB_LONGVAR_MAX

private static final int SYB_LONGVAR_MAX

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MS_LONGVAR_MAX

private static final int MS_LONGVAR_MAX

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SYB_CHUNK_SIZE

private static final int SYB_CHUNK_SIZE

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Constant Field Values

types

private static final TdsData.TypeInfo[] types

Array of TDS data type descriptors.

DEFAULT_SCALE

static final int DEFAULT_SCALE

Default Decimal Scale.

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Constant Field Values

DEFAULT_PRECISION_28

static final int DEFAULT_PRECISION_28

Default precision for SQL Server 6.5 and 7.

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Constant Field Values

DEFAULT_PRECISION_38

static final int DEFAULT_PRECISION_38

Default precision for Sybase and SQL Server 2000 and newer.

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Constant Field Values

Constructor Detail

TdsData

private TdsData()

Private constructor to prevent users creating an actual instance of this class.

Method Detail

getCollation

static int getCollation(ResponseStream in,
                        ColInfo ci)
                 throws java.io.IOException

TDS 8 supplies collation information for character data types.

Parameters:

in - the server response stream

ci - the column descriptor

Returns:

the number of bytes read from the stream as an int

Throws:

java.io.IOException

setColumnCharset

static void setColumnCharset(ColInfo ci,
                             ConnectionJDBC2 connection)
                      throws java.sql.SQLException

Set the charsetInfo field of ci according to the value of its collation field.

The Connection is used to find out whether a specific charset was requested. In this case, the column charset will be ignored.

Parameters:

ci - the ColInfo instance to update

connection - a Connection instance to check whether it has a fixed charset or not

Throws:

java.sql.SQLException - if a CharsetInfo is not found for this particular column collation

readType

static int readType(ResponseStream in,
                    ColInfo ci)
             throws java.io.IOException,
                    ProtocolException

Read the TDS datastream and populate the ColInfo parameter with data type and related information.

The type infomation conforms to one of the following formats:

1. [int1 type] - eg SYBINT4.
2. [int1 type] [int1 buffersize] - eg VARCHAR < 256
3. [int1 type] [int2 buffersize] - eg VARCHAR > 255.
4. [int1 type] [int4 buffersize] [int1 tabnamelen] [int1*n tabname] - eg text.
5. [int1 type] [int4 buffersize] - eg sql_variant.
6. [int1 type] [int1 buffersize] [int1 precision] [int1 scale] - eg decimal.

For TDS 8 large character types include a 5 byte collation field after the buffer size.

Parameters:

in - The server response stream.

ci - The ColInfo column descriptor object.

Returns:

The number of bytes read from the input stream.

Throws:

java.io.IOException

ProtocolException

readData

static java.lang.Object readData(ConnectionJDBC2 connection,
                                 ResponseStream in,
                                 ColInfo ci)
                          throws java.io.IOException,
                                 ProtocolException

Read the TDS data item from the Response Stream.

The data size is either implicit in the type for example fixed size integers, or a count field precedes the actual data. The size of the count field varies with the data type.

Parameters:

connection - an object reference to the caller of this method; must be a Connection, Statement or ResultSet

in - The server ResponseStream.

ci - The ColInfo column descriptor object.

Returns:

The data item Object or null.

Throws:

java.io.IOException

ProtocolException

isSigned

static boolean isSigned(ColInfo ci)

Retrieve the signed status of the column.

Parameters:

ci - the column meta data

Returns:

true if the column is a signed numeric.

isCollation

static boolean isCollation(ColInfo ci)

Retrieve the collation status of the column.

TDS 8.0 character columns include collation information.

Parameters:

ci - the column meta data

Returns:

true if the column requires collation data.

isCurrency

static boolean isCurrency(ColInfo ci)

Retrieve the currency status of the column.

Parameters:

ci - The column meta data.

Returns:

boolean true if the column is a currency type.

isSearchable

static boolean isSearchable(ColInfo ci)

Retrieve the searchable status of the column.

Parameters:

ci - the column meta data

Returns:

true if the column is not a text or image type.

isUnicode

static boolean isUnicode(ColInfo ci)

Determines whether the column is Unicode encoded.

Parameters:

ci - the column meta data

Returns:

true if the column is Unicode encoded

fillInType

static void fillInType(ColInfo ci)
                throws java.sql.SQLException

Fill in the TDS native type code and all other fields for a ColInfo instance with the JDBC type set.

Parameters:

ci - the ColInfo instance

Throws:

java.sql.SQLException

getNativeType

static void getNativeType(ConnectionJDBC2 connection,
                          ParamInfo pi)
                   throws java.sql.SQLException

Retrieve the TDS native type code for the parameter.

Parameters:

connection - the connectionJDBC object

pi - the parameter descriptor

Throws:

java.sql.SQLException

getTds5ParamSize

static int getTds5ParamSize(java.lang.String charset,
                            boolean isWideChar,
                            ParamInfo pi,
                            boolean useParamNames)

Calculate the size of the parameter descriptor array for TDS 5 packets.

Parameters:

charset - The encoding character set.

isWideChar - True if multi byte encoding.

pi - The parameter to describe.

useParamNames - True if named parameters should be used.

Returns:

The size of the parameter descriptor as an int.

writeTds5ParamFmt

static void writeTds5ParamFmt(RequestStream out,
                              java.lang.String charset,
                              boolean isWideChar,
                              ParamInfo pi,
                              boolean useParamNames)
                       throws java.io.IOException

Write a TDS 5 parameter format descriptor.

Parameters:

out - The server RequestStream.

charset - The encoding character set.

isWideChar - True if multi byte encoding.

pi - The parameter to describe.

useParamNames - True if named parameters should be used.

Throws:

java.io.IOException

writeTds5Param

static void writeTds5Param(RequestStream out,
                           CharsetInfo charsetInfo,
                           ParamInfo pi)
                    throws java.io.IOException,
                           java.sql.SQLException

Write the actual TDS 5 parameter data.

Parameters:

out - the server RequestStream

charsetInfo - the encoding character set

pi - the parameter to output

Throws:

java.io.IOException

java.sql.SQLException

putCollation

static void putCollation(RequestStream out,
                         ParamInfo pi)
                  throws java.io.IOException

TDS 8 requires collation information for char data descriptors.

Parameters:

out - The Server request stream.

pi - The parameter descriptor.

Throws:

java.io.IOException

writeParam

static void writeParam(RequestStream out,
                       CharsetInfo charsetInfo,
                       byte[] collation,
                       ParamInfo pi)
                throws java.io.IOException

Write a parameter to the server request stream.

Parameters:

out - the server request stream

charsetInfo - the default character set

collation - the default SQL Server 2000 collation

pi - the parameter descriptor

Throws:

java.io.IOException

getDatetimeValue

private static java.lang.Object getDatetimeValue(ResponseStream in,
                                                 int type)
                                          throws java.io.IOException,
                                                 ProtocolException

Get a DATETIME value from the server response stream.

Parameters:

in - The server response stream.

type - The TDS data type.

Returns:

The java.sql.Timestamp value or null.

Throws:

java.io.IOException

ProtocolException

putDateTimeValue

private static void putDateTimeValue(RequestStream out,
                                     DateTime value)
                              throws java.io.IOException

Output a java.sql.Date/Time/Timestamp value to the server as a Sybase datetime value.

Parameters:

out - the server request stream

value - the date value to write

Throws:

java.io.IOException

getMoneyValue

private static java.lang.Object getMoneyValue(ResponseStream in,
                                              int type)
                                       throws java.io.IOException,
                                              ProtocolException

Read a MONEY value from the server response stream.

Parameters:

in - The server response stream.

type - The TDS data type.

Returns:

The java.math.BigDecimal value or null.

Throws:

java.io.IOException

ProtocolException

getVariant

private static java.lang.Object getVariant(ConnectionJDBC2 connection,
                                           ResponseStream in)
                                    throws java.io.IOException,
                                           ProtocolException

Read a MSQL 2000 sql_variant data value from the input stream.

SQL_VARIANT has the following structure:

1. INT4 total size of data
2. INT1 TDS data type (text/image/ntext/sql_variant not allowed)
3. INT1 Length of extra type descriptor information
4. Optional additional type info required by some types
5. byte[0...n] the actual data

Parameters:

connection - used to obtain collation/charset information

in - the server response stream

Returns:

the SQL_VARIANT data

Throws:

java.io.IOException

ProtocolException

getMSTypeName

public static java.lang.String getMSTypeName(java.lang.String typeName,
                                             int tdsType)

For SQL 2005 This routine will modify the meta data to allow the caller to distinguish between varchar(max) and text or varbinary(max) and image or nvarchar(max) and ntext.

Parameters:

typeName - the SQL type returned by sp_columns

tdsType - the TDS type returned by sp_columns

Returns:

the (possibly) modified SQL type name as a String

getTdsVersion

public static int getTdsVersion(int rawTdsVersion)

Extract the TDS protocol version from the value returned by the server in the LOGINACK packet.

Parameters:

rawTdsVersion - the TDS protocol version as returned by the server

Returns:

the jTDS internal value for the protocol version (i.e one of the Driver.TDSXX values)

canEncode

private static boolean canEncode(java.lang.String value,
                                 java.lang.String charset)

Establish if a String can be converted to a byte based character set.

Parameters:

value - The String to test.

charset - The server character set in force.

Returns:

boolean true if string can be converted.