WebLogic Type 4 JDBC Drivers

The MS SQL Server Driver

The following sections describe how to configure and use the BEA WebLogic Type 4 JDBC SQL Server driver:

Note: The BEA WebLogic Type 4 JDBC MS SQL Server driver (the subject of this chapter) replaces the WebLogic jDriver for Microsoft SQL Server, which is deprecated. The new driver offers JDBC 3.0 compliance, support for some JDBC 2.0 extensions, and better performance. BEA recommends that you use the new BEA WebLogic Type 4 JDBC MS SQL Server driver in place of the WebLogic jDriver for Microsoft SQL Server.

SQL Server Database Version Support

The BEA WebLogic Type 4 JDBC MS SQL Server driver (the "SQL Server driver") supports the following database management system versions:

Microsoft SQL Server 7.0
Microsoft SQL Server 2000 (including SP1, SP2, and SP3a)
Microsoft SQL Server 2000 Enterprise Edition (64-bit) on Windows

To use JDBC distributed transactions through JTA, you must install stored procedures for SQL Server. See Installing Stored Procedures for JTA for details.

Driver Class

The driver classes for the BEA WebLogic Type 4 JDBC MS SQL Server driver are:

XA: weblogic.jdbcx.sqlserver.SQLServerDataSource

Non-XA: weblogic.jdbc.sqlserver.SQLServerDriver

URL

To connect to a Microsoft SQL Server database, use the following URL format:

jdbc:bea:sqlserver://dbserver:port

Connecting to Named Instances

Microsoft SQL Server supports multiple instances of a SQL Server database running concurrently on the same server. An instance is identified by an instance name.

To connect to a named instance using a connection URL, use the following URL format:

jdbc:bea:sqlserver://server_name\\instance_name

Note: The first back slash character (\) in \\instance_name is an escape character.

where:

server_name is the IP address or hostname of the server.

instance_name is the name of the instance to which you want to connect on the server.

For example, the following connection URL connects to an instance named instance1 on server1:

jdbc:bea:sqlserver://server1\\instance1;User=test;Pasword=secret

SQL Server Connection Properties

Table 5-1 lists the JDBC connection properties supported by the SQL Server driver, and describes each property. You can use these connection properties in a JDBC data source configuration in your WebLogic Server domain. To specify a property, use the following form in the JDBC data source configuration:

property=value

Note: All connection string property names are case-insensitive. For example, Password is the same as password.

Table 5-1 SQL Server Connection Properties

Property	Description
AlwaysReportTriggerResults OPTIONAL	{true \| false}. Determines how the driver reports results generated by database triggers (procedures that are stored in the database and executed, or fired, when a table is modified). If set to true, the driver returns all results, including results generated by triggers. Multiple trigger results are returned one at a time. Use the Statement.getMoreResults method to retrieve individual trigger results. Warnings and errors are reported in the results as they are encountered. If set to false, the driver does not report trigger results if the statement is a single Insert, Update, or Delete statement. In this case, the only result that is returned is the update count generated by the statement that was executed (if errors do not occur). Although trigger results are ignored, any errors generated by the trigger are reported. Any warnings generated by the trigger are enqueued. If errors are reported, the update count is not reported. The default is false.
CodePageOverride OPTIONAL	Specifies the code page the driver uses when converting character data. The specified code page overrides the default database code page. All character data retrieved from or written to the database is converted using the specified code page. The value must be a string containing the name of a valid code page supported by your Java Virtual Machine, for example, CodePageOverride=CP950. If a value is set for the CodePageOverride property and the SendStringParametersAsUnicode property is set to true, the driver ignores the SendStringParametersAsUnicode property and generates a warning. The driver always sends parameters using the code page specified by CodePageOverride if this property is specified.
ConnectionRetryCount OPTIONAL	The number of times the driver retries connections to a database server until a successful connection is established. Valid values are 0 and any positive integer. If set to 0, the driver does not retry a connection to the list of database servers if a connection is not established on the driver's first pass through the list. The default is 0.
ConnectionRetryDelay OPTIONAL	The number of seconds the driver waits before retrying connection attempts when ConnectionRetryCount is set to a positive integer. The default is 3.
DatabaseName OPTIONAL	The name of the database to which you want to connect.
HostProcess OPTIONAL	The process ID of the application connecting to Microsoft SQL Server. The value of this property appears in the hostprocess column of the master.dbo.sysprocesses table and may be useful for database administration purposes. The default is 0.
InsensitiveResultSetBufferSize OPTIONAL	{-1 \| 0 \| x}. Determines the amount of memory used by the driver to cache insensitive result set data. It must have one of the following values: If set to -1, the driver caches all insensitive result set data in memory. If the size of the result set exceeds available memory, an OutOfMemoryException is generated. Because the need to write result set data to disk is eliminated, the driver processes the data more efficiently. If set to 0, the driver caches all insensitive result set data in memory, up to a maximum of 2 GB. If the size of the result set data exceeds available memory, the driver pages the result set data to disk. Because result set data may be written to disk, the driver may have to reformat the data to write it correctly to disk. If set to x, where x is a positive integer, the driver caches all insensitive result set data in memory, using this value to set the size (in KB) of the memory buffer for caching insensitive result set data. If the size of the result set data exceeds the buffer size, the driver pages the result set data to disk. Because the result set data may be written to disk, the driver may have to reformat the data to write it correctly to disk. Specifying a buffer size that is a power of 2 results in more efficient memory use. The default is 2048 (KB).
NetAddress OPTIONAL	The Media Access Control (MAC) address of the network interface card of the application connecting to Microsoft SQL Server. The value of this property appears in the net_address column of the master.dbo.sysprocesses table and may be useful for database administration purposes. The default is 000000000000.
Password	A case-insensitive password used to connect to your Microsoft SQL Server database.
PortNumber OPTIONAL	The TCP port of the primary database server that is listening for connections to the Microsoft SQL Server database. The default is 1433.
ProgramName OPTIONAL	The name of the application connecting to Microsoft SQL Server. The value of this property appears in the program_name column of the master.dbo.sysprocesses table and may be useful for database administration purposes. The default is an empty string.
SelectMethod OPTIONAL	{direct \| cursor}. A hint to the driver that determines whether the driver requests a database cursor for Select statements. Performance and behavior of the driver are affected by this property, which is defined as a hint because the driver may not always be able to satisfy the requested method. Direct—When the driver uses the Direct method, the database server sends the complete result set in a single response to the driver when responding to a query. A server-side database cursor is not created. Typically, responses are not cached by the driver. Using this method, the driver must process all the response to a query before another query is submitted. If another query is submitted (using a different statement on the same connection, for example), the driver caches the response to the first query before submitting the second query. Typically, the Direct method performs better than the Cursor method. Cursor—When the driver uses the Cursor method, a server-side cursor is requested. The rows are retrieved from the server in blocks when returning forward-only result sets. The JDBC Statement method setFetchSize can be used to control the number of rows that are retrieved for each request. Performance tests show that the value of setFetchSize significantly impacts performance when the Cursor method is used. There is no simple rule for determining the setFetchSize value that you should use. BEA recommends that you experiment with different setFetchSize values to determine which value gives the best performance for your application. The Cursor method is useful for queries that produce a large amount of data, particularly if multiple open result sets are used. The default is Direct.
SendStringParametersAsUnicode OPTIONAL	{true \| false}. Determines whether string parameters are sent to the Microsoft SQL Server database in Unicode or in the default character encoding of the database. If set to true, string parameters are sent to Microsoft SQL Server in Unicode. If set to false, string parameters are sent in the default encoding, which can improve performance because the server does not need to convert Unicode characters to the default encoding. You should, however, use default encoding only if the parameter string data you specify is the same as the default encoding of the database. The default is true. If a value is specified for the CodePageOverride property and this property is set to true, this property is ignored and a warning is generated.
ServerName	Specifies either the IP address or the server name (if your network supports named servers) of the primary database server. For example, 122.23.15.12 or SQLServerServer. To connect to a named instance, specify `server_name\\instance_name` for this property, where `server_name` is the IP address and `instance_name` is the name of the instance to which you want to connect on the specified server.
User	The case-insensitive user name used to connect to your Microsoft SQL Server database.
UseServerSideUpdatableCursors	{true \| false}. Determines whether the driver uses server-side cursors when an updatable result set is requested. If set to true, server-side updatable cursors are created when an updatable result set is requested. If set to false, the default updatable result set functionality is used. The default is false. See Server-Side Updatable Cursors for more information about using server-side updatable cursors.
WSID OPTIONAL	The workstation ID, which typically is the network name of the computer on which the application resides. If specified, this value is stored in the hostname column of the master.dbo.sysprocesses table and can be returned by sp_who and the Transact-SQL HOST_NAME function. The value can be useful for database administration purposes. The default is an empty string.
XATransactionGroup OPTIONAL	The transaction group ID that identifies any transactions initiated by the connection. This ID can be used for distributed transaction cleanup purposes.

Property

Description

AlwaysReportTriggerResults

OPTIONAL

{true | false}. Determines how the driver reports results generated by database triggers (procedures that are stored in the database and executed, or fired, when a table is modified).

If set to true, the driver returns all results, including results generated by triggers. Multiple trigger results are returned one at a time. Use the Statement.getMoreResults method to retrieve individual trigger results. Warnings and errors are reported in the results as they are encountered.

If set to false, the driver does not report trigger results if the statement is a single Insert, Update, or Delete statement. In this case, the only result that is returned is the update count generated by the statement that was executed (if errors do not occur). Although trigger results are ignored, any errors generated by the trigger are reported. Any warnings generated by the trigger are enqueued. If errors are reported, the update count is not reported.

The default is false.

CodePageOverride

OPTIONAL

Specifies the code page the driver uses when converting character data. The specified code page overrides the default database code page. All character data retrieved from or written to the database is converted using the specified code page. The value must be a string containing the name of a valid code page supported by your Java Virtual Machine, for example, CodePageOverride=CP950.

If a value is set for the CodePageOverride property and the SendStringParametersAsUnicode property is set to true, the driver ignores the SendStringParametersAsUnicode property and generates a warning. The driver always sends parameters using the code page specified by CodePageOverride if this property is specified.

ConnectionRetryCount

OPTIONAL

The number of times the driver retries connections to a database server until a successful connection is established. Valid values are 0 and any positive integer.

If set to 0, the driver does not retry a connection to the list of database servers if a connection is not established on the driver's first pass through the list.

The default is 0.

ConnectionRetryDelay

OPTIONAL

The number of seconds the driver waits before retrying connection attempts when ConnectionRetryCount is set to a positive integer.

The default is 3.

DatabaseName

OPTIONAL

The name of the database to which you want to connect.

HostProcess

OPTIONAL

The process ID of the application connecting to Microsoft SQL Server. The value of this property appears in the hostprocess column of the master.dbo.sysprocesses table and may be useful for database administration purposes.

The default is 0.

InsensitiveResultSetBufferSize

OPTIONAL

{-1 | 0 | x}. Determines the amount of memory used by the driver to cache insensitive result set data. It must have one of the following values:

If set to -1, the driver caches all insensitive result set data in memory. If the size of the result set exceeds available memory, an OutOfMemoryException is generated. Because the need to write result set data to disk is eliminated, the driver processes the data more efficiently.

If set to 0, the driver caches all insensitive result set data in memory, up to a maximum of 2 GB. If the size of the result set data exceeds available memory, the driver pages the result set data to disk. Because result set data may be written to disk, the driver may have to reformat the data to write it correctly to disk.

If set to x, where x is a positive integer, the driver caches all insensitive result set data in memory, using this value to set the size (in KB) of the memory buffer for caching insensitive result set data. If the size of the result set data exceeds the buffer size, the driver pages the result set data to disk. Because the result set data may be written to disk, the driver may have to reformat the data to write it correctly to disk. Specifying a buffer size that is a power of 2 results in more efficient memory use.

The default is 2048 (KB).

NetAddress

OPTIONAL

The Media Access Control (MAC) address of the network interface card of the application connecting to Microsoft SQL Server. The value of this property appears in the net_address column of the master.dbo.sysprocesses table and may be useful for database administration purposes.

The default is 000000000000.

Password

A case-insensitive password used to connect to your Microsoft SQL Server database.

PortNumber

OPTIONAL

The TCP port of the primary database server that is listening for connections to the Microsoft SQL Server database.

The default is 1433.

ProgramName

OPTIONAL

The name of the application connecting to Microsoft SQL Server. The value of this property appears in the program_name column of the master.dbo.sysprocesses table and may be useful for database administration purposes.

The default is an empty string.

SelectMethod

OPTIONAL

{direct | cursor}. A hint to the driver that determines whether the driver requests a database cursor for Select statements. Performance and behavior of the driver are affected by this property, which is defined as a hint because the driver may not always be able to satisfy the requested method.

Direct—When the driver uses the Direct method, the database server sends the complete result set in a single response to the driver when responding to a query. A server-side database cursor is not created. Typically, responses are not cached by the driver. Using this method, the driver must process all the response to a query before another query is submitted. If another query is submitted (using a different statement on the same connection, for example), the driver caches the response to the first query before submitting the second query. Typically, the Direct method performs better than the Cursor method.

Cursor—When the driver uses the Cursor method, a server-side cursor is requested. The rows are retrieved from the server in blocks when returning forward-only result sets. The JDBC Statement method setFetchSize can be used to control the number of rows that are retrieved for each request. Performance tests show that the value of setFetchSize significantly impacts performance when the Cursor method is used. There is no simple rule for determining the setFetchSize value that you should use. BEA recommends that you experiment with different setFetchSize values to determine which value gives the best performance for your application. The Cursor method is useful for queries that produce a large amount of data, particularly if multiple open result sets are used.

The default is Direct.

SendStringParametersAsUnicode

OPTIONAL

{true | false}. Determines whether string parameters are sent to the Microsoft SQL Server database in Unicode or in the default character encoding of the database.

If set to true, string parameters are sent to Microsoft SQL Server in Unicode.

If set to false, string parameters are sent in the default encoding, which can improve performance because the server does not need to convert Unicode characters to the default encoding. You should, however, use default encoding only if the parameter string data you specify is the same as the default encoding of the database.

The default is true.

If a value is specified for the CodePageOverride property and this property is set to true, this property is ignored and a warning is generated.

ServerName

Specifies either the IP address or the server name (if your network supports named servers) of the primary database server. For example, 122.23.15.12 or SQLServerServer.

To connect to a named instance, specify server_name\\instance_name for this property, where server_name is the IP address and instance_name is the name of the instance to which you want to connect on the specified server.

User

The case-insensitive user name used to connect to your Microsoft SQL Server database.

UseServerSideUpdatableCursors

{true | false}. Determines whether the driver uses server-side cursors when an updatable result set is requested.

If set to true, server-side updatable cursors are created when an updatable result set is requested.

If set to false, the default updatable result set functionality is used.

The default is false.

See Server-Side Updatable Cursors for more information about using server-side updatable cursors.

WSID

OPTIONAL

The workstation ID, which typically is the network name of the computer on which the application resides. If specified, this value is stored in the hostname column of the master.dbo.sysprocesses table and can be returned by sp_who and the Transact-SQL HOST_NAME function. The value can be useful for database administration purposes.

The default is an empty string.

XATransactionGroup

OPTIONAL

The transaction group ID that identifies any transactions initiated by the connection. This ID can be used for distributed transaction cleanup purposes.

Data Types

Table 5-2 lists the data types supported by the SQL Server driver in SQL Server 7 and SQL Server 2000 and how they are mapped to the JDBC data types.

Table 5-2 Data Types Supported by SQL Server 7 and SQL Server 2000

SQL Server Data Type	JDBC Data Type
binary	BINARY
bit	BIT
char	CHAR
datetime	TIMESTAMP
decimal	DECIMAL
decimal() identity	DECIMAL
float	FLOAT
image	LONGVARBINARY
int	INTEGER
int identity	INTEGER
money	DECIMAL
nchar	CHAR
ntext	LONGVARCHAR
numeric	NUMERIC
numeric() identity	NUMERIC
nvarchar	VARCHAR
real	REAL
smalldatetime	TIMESTAMP
smallint	SMALLINT
smallint identity	SMALLINT
smallmoney	DECIMAL
sysname	VARCHAR
text	LONGVARCHAR
timestamp	BINARY
tinyint	TINYINT
tinyint identity	TINYINT
uniqueidentifier	CHAR
varbinary	VARBINARY
varchar	VARCHAR

Table 5-3 lists additional data types supported by SQL Server 2000 only.

Table 5-3 Addition Data Types Supported by SQL Server 2000

SQL Server Data Type	JDBC Data Type
bigint	BIGINT
bigint identity	BIGINT
sql_variant	VARCHAR

See GetTypeInfo for more information about data types.

SQL Escape Sequences

See SQL Escape Sequences for JDBC, for information about the SQL escape sequences supported by the SQL Server driver.

Isolation Levels

The SQL Server driver supports the Read Committed, Read Uncommitted, Repeatable Read, and Serializable isolation levels. The default is Read Committed.

Using Scrollable Cursors

The SQL Server driver supports scroll-sensitive result sets, scroll-insensitive result sets, and updatable result sets.

Note: When the SQL Server driver cannot support the requested result set type or concurrency, it automatically downgrades the cursor and generates one or more SQLWarnings with detailed information.

Server-Side Updatable Cursors

In most cases, using server-side updatable cursors is faster, but server-side updatable cursors cannot be used with insensitive result sets or with sensitive result sets that do not have a primary key. By default, the MS SQL Server driver allows insensitive result sets and sensitive result sets that do not contain a primary key to be updatable. To use server-side cursors when an updatable result set is requested, you set the UseServerSideUpdatableCursors property.

When the UseServerSideUpdatableCursors property is set to true and a scroll-insensitive updatable result set is requested, the driver downgrades the request to a scroll-insensitive read-only result set. Similarly, when a scroll-sensitive updatable result set is requested and the table does not contain a primary key, the driver downgrades the request to a scroll-sensitive read-only result set. In either case, a warning is generated.

When server-side updatable cursors are used with sensitive result sets that contain a primary key, any changes you make to the result set are visible. Using the default behavior of the driver, those changes would not be visible.

Installing Stored Procedures for JTA

To use JDBC distributed transactions through JTA, your system administrator should use the following procedure to install Microsoft SQL Server JDBC XA procedures. This procedure must be repeated for each MS SQL Server installation that will be involved in a distributed transaction.

To install stored procedures for JTA:

Copy the sqljdbc.dll and instjdbc.sql files from the WL_HOME\server\lib directory to the SQL_Server_Root/bin directory of the MS SQL Server database server, where WL_HOME is the directory in which WebLogic server is installed, typically c:\bea\weblogic81.

Note: If you are installing stored procedures on a database server with multiple Microsoft SQL Server instances, each running SQL Server instance must be able to locate the sqljdbc.dll file. Therefore the sqljdbc.dll file needs to be anywhere on the global PATH or on the application-specific path. For the application-specific path, place the sqljdbc.dll file into the <drive>:\Program Files\Microsoft SQL Server\MSSQL$<Instance 1 Name>\Binn directory for each instance.

From the database server, use the ISQL utility to run the instjdbc.sql script. The system administrator should back up the master database before running instjdbc.sql.

At a command prompt, use the following syntax to run instjdbc.sql: ISQL -Usa -Psa_password -Sserver_name -ilocation\instjdbc.sql
where:
sa_password is the password of the system administrator.
server_name is the name of the server on which SQL Server resides.
location is the full path to instjdbc.sql. (You copied this script to the SQL_Server_Root/bin directory in step 1.)
The instjdbc.sql script generates many messages. In general, these messages can be ignored; however, the system administrator should scan the output for any messages that may indicate an execution error. The last message should indicate that instjdbc.sql ran successfully. The script fails when there is insufficient space available in the master database to store the JDBC XA procedures or to log changes to existing procedures.

Large Object (LOB) Support

Although Microsoft SQL Server does not define a Blob or Clob data type, the SQL Server driver allows you to retrieve and update long data, specifically LONGVARBINARY and LONGVARCHAR data, using JDBC methods designed for Blobs and Clobs. When using these methods to update long data as Blobs or Clobs, the updates are made to the local copy of the data contained in the Blob or Clob object.

Retrieving and updating long data using JDBC methods designed for Blobs and Clobs provides some of the same advantages as retrieving and updating Blobs and Clobs. For example, using Blobs and Clobs:

Provides random access to data
Allows searching for patterns in the data, such as retrieving long data that begins with a specific character string

To provide these advantages of Blobs and Clobs, data must be cached. Because data is cached, you will incur a performance penalty, particularly if the data is read once sequentially. This performance penalty can be severe if the size of the long data is larger than available memory.

Batch Inserts and Updates

The SQL Server driver implementation for batch Inserts and Updates is JDBC 3.0 compliant. When the SQL Server driver detects an error in a statement or parameter set in a batch Insert or Update, it generates a BatchUpdateException and continues to execute the remaining statements or parameter sets in the batch. The array of update counts contained in the BatchUpdateException contain one entry for each statement or parameter set. Any entries for statements or parameter sets that failed contain the value Statement.EXECUTE_FAILED.

Parameter Metadata Support

The SQL Server driver supports returning parameter metadata for the following forms of SQL:

INSERT INTO foo VALUES (?, ?, ?)
INSERT INTO foo (col1, col2, col3) VALUES (?, ?, ?)
UPDATE foo SET col1=?, col2=?, col3=? WHERE col1 operator ? [{AND | OR} col2 operator ?]

where operator is any of the following SQL operators: =, <, >, <=, >=, and <>.

Auto-Generated Keys Support

The SQL Server driver supports retrieving the values of auto-generated keys. An auto-generated key returned by the SQL Server driver is the value of an identity column.

How you return those values depends on whether you are using an Insert statement that contains parameters:

When using an Insert statement that contains no parameters, the MS SQL Server driver supports the following form of the Statement.execute and Statement.executeUpdate methods to inform the driver to return the values of auto-generated keys:

Statement.execute (String sql, int autoGeneratedKeys)
Statement.executeUpdate (String sql, int autoGeneratedKeys)

When using an Insert statement that contains parameters, the MS SQL Server driver supports the following form of the Connection.prepareStatement method to inform the driver to return the values of auto-generated keys:

Connection.prepareStatement (String sql, int autoGeneratedKeys)

The application fetches the values of generated keys from the driver using the Statement.getGeneratedKeys () method.