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分类: Java
2014-06-18 08:29:41
Many properties can be specified when connecting to a server database using JDBC. All properties are optional and can be specified either as part of the URL or in a java.util.Properties object. If a property is set in both the URL and a Properties object, the value in the URL will be used.
The following tables list the different connection properties that are recognized by this driver. Some of these properties affect performance and others are server job attributes. The tables organize the properties into the following categories:
General properties are system attributes that specify the user, password, and whether a prompt is necessary to connect to the server.
General property | Description | Required | Choices | Default |
---|---|---|---|---|
"password" | Specifies the password for connecting to the server. If none is specified, then the user will be prompted, unless the "prompt" property is set to "false", in which case an attempt to connect will fail. | no | server password | (user will be prompted) |
"prompt" | Specifies whether the user is prompted if a user name or password is needed to connect to the server. If a connection cannot be made without prompting the user, and this property is set to "false", then an attempt to connect will fail. | no |
|
"true" |
"user" | Specifies the user name for connecting to the server. If none is specified, then the user will be prompted, unless the "prompt" property is set to "false", in which case an attempt to connect will fail. | no | server user | (user will be prompted) |
Server properties specify attributes that govern transactions, libraries, and databases.
Server property | Description | Required | Choices | Default |
---|---|---|---|---|
"cursor hold" | Specifies whether to hold the cursor across transactions. If this property is set to "true", cursors are not closed when a transaction is committed or rolled back. All resources acquired during the unit of work are held, but locks on specific rows and objects implicitly acquired during the unit of work are released. | no |
|
"true" |
"cursor sensitivity" |
Specifies the cursor sensitivity to request from the database. The behavior depends on the resultSetType:
This property is ignored when connecting to systems running V5R1 and earlier versions of i5/OS?. |
no |
|
"" |
"database name" |
Specifies the database to use for the connection, including one stored in an . This property applies only when connecting to a V5R2 or later version of i5/OS. When you specify a database name, the name must exist in the relational database directory on the server. The following criteria determine which database is accessed:
|
no | Database name "*SYSBAS" | The database name specified in the job description for the user profile is used. When the job description does not specify a database name, the system default database is used. |
"libraries" |
Specifies one or more libraries that you want to add to or replace the library list of the server job, and optionally sets the default library (default schema). Library list The server uses specified libraries to resolve unqualified stored procedure names, and stored procedures use them to resolve unqualified names. To specify multiple libraries, use commas or spaces to separate individual entries. You can use *LIBL as a placeholder for the current library list of the server job:
For more information about library list properties, see . Default schema The server uses the default schema to resolve unqualified names in SQL statements. For example, in the statement "SELECT * FROM MYTABLE", the server looks only in the default schema for MYTABLE. You can specify the default schema on the connection URL. When you do not specify the default schema on the connection URL, the following conditions apply, depending on whether you use SQL Naming or System Naming.
|
no | List of server libraries, separated by commas or spaces | "*LIBL" |
"maximum precision" | Specifies the maximum decimal precision the database might use. | no |
|
"31" |
"maximum scale" | Specifies the maximum scale the database might use. | no | "0"-"63" | "31" |
"minimum divide scale" | Specifies the minimum scale value for the result of decimal division. | no |
|
"0" |
"package ccsid" | Specifies the character encoding to use for the SQL package and any statements sent to the server. | no |
|
"13488" |
"rollback cursor hold" | Specifies whether to hold the cursor after a rollback. If this property is set to "true", cursors are held after a transaction is rolled back. | no |
|
"false" |
"transaction isolation" | Specifies the default transaction isolation. | no |
|
"read uncommitted" |
"translate hex" | Specifies how hexadecimal literals are interpreted. | no |
|
"character" |
"true autocommit" | Specifies whether the connection should use true auto commit support. True autocommit means that autocommit is on and is running under a isolation level other than *NONE. By default, the driver handles autocommit by running under the server isolation level of *NONE. | no |
|
"false" |
"xa loosely coupled support" |
Specifies whether lock sharing is allowed for loosely
coupled transaction branches.
Note: This setting is ignored when running to i5/OS V5R3
or earlier.
|
no |
|
"0" |
Format properties specify date and time formats, date and decimal separators, and table naming conventions used within SQL statements.
Format property | Description | Required | Choices | Default |
---|---|---|---|---|
"date format" | Specifies the date format used in date literals within SQL statements. | no |
|
(server job) |
"date separator" | Specifies the date separator used in date literals within SQL statements. This property has no effect unless the "date format" property is set to "julian", "mdy", "dmy" or "ymd". | no |
|
(server job) |
"decimal separator" | Specifies the decimal separator used in numeric literals within SQL statements. | no |
|
(server job) |
"naming" | Specifies the naming convention used when referring to tables. | no | "sql" (as in schema.table) "system" (as in schema/table) | "sql" |
"time format" | Specifies the time format used in time literals within SQL statements. | no |
|
(server job) |
"time separator" | Specifies the time separator used in time literals within SQL statements. This property has no effect unless the "time format" property is set to "hms". | no |
|
(server job) |
Performance properties are attributes that include caching, data conversion, data compression, and prefetching that affect performance.
Performance property | Description | Required | Choices | Default |
---|---|---|---|---|
"big decimal" | Specifies whether an intermediate java.math.BigDecimal object is used for packed and zoned decimal conversions. If this property is set to "true", an intermediate java.math.BigDecimal object is used for packed and zoned decimal conversions as described by the JDBC specification. If this property is set to "false", no intermediate objects are used for packed and zoned decimal conversions. Instead, such values are converted directly to and from Java double values. Such conversions will be faster but may not follow all conversion and data truncation rules documented by the JDBC specification. | no |
|
"true" |
"block criteria" |
Specifies the criteria for retrieving data from the server in blocks
of records. Specifying a non-zero value for this property will reduce the
frequency of communication to the server, and therefore improve performance.
Ensure that record blocking is off if the cursor is going to be used for subsequent UPDATEs, or else the row that is updated will not necessarily be the current row. |
no |
|
"2" |
"block size" | Specifies the block size (in kilobytes) to retrieve from the server and cache on the client. This property has no effect unless the "block criteria" property is non-zero. Larger block sizes reduce the frequency of communication to the server, and therefore may improve performance. | no |
|
"32" |
"data compression" | Specifies whether result set data is compressed. If this property is set to "true", then result set data is compressed. If this property is set to "false", then result set data is not compressed. Data compression may improve performance when retrieving large result sets. | no |
|
"true" |
"extended dynamic" | Specifies whether to use extended dynamic support. Extended dynamic support provides a mechanism for caching dynamic SQL statements on the server. The first time a particular SQL statement is prepared, it is stored in a SQL package on the server. If the package does not exist, it is automatically created. On subsequent prepares of the same SQL statement, the server can skip a significant part of the processing by using information stored in the SQL package. If this is set to "true", then a package name must be set using the "package" property. | no |
|
"false" |
"lazy close" | Specifies whether to delay closing cursors until subsequent requests. This will improve overall performance by reducing the total number of requests. | no |
|
"false" |
"lob threshold" | Specifies the maximum LOB (large object) size (in bytes) that can be retrieved as part of a result set. LOBs that are larger than this threshold will be retrieved in pieces using extra communication to the server. Larger LOB thresholds will reduce the frequency of communication to the server, but will download more LOB data, even if it is not used. Smaller LOB thresholds may increase frequency of communication to the server, but will only download LOB data as it is needed. | no | "0" - "16777216" | "32768" |
"package" | Specifies the base name of the SQL package. Note that only the first seven characters are used to generate the name of the SQL package on the server. This property has no effect unless the "extended dynamic" property is set to "true". In addition, this property must be set if the "extended dynamic" property is set to "true". | no | SQL package | "" |
"package add" | Specifies whether to add newly prepared statements to the SQL package specified on the "package" property. This property has no effect unless the "extended dynamic" property is set to "true". | no |
|
"true" |
"package cache" | Specifies whether to cache a subset of the SQL package information in client memory. Caching SQL packages locally reduces the amount of communication to the server for prepares and describes. This property has no effect unless the "extended dynamic" property is set to "true". | no |
|
"false" |
"package criteria" | Specifies the type of SQL statements to be stored in the SQL package. This can be useful to improve the performance of complex join conditions. This property has no effect unless the "extended dynamic" property is set to "true". | no |
|
"default" |
"package error" | Specifies the action to take when SQL package errors occur. When a SQL package error occurs, the driver will optionally throw a SQLException or post a notice to the Connection, based on the value of this property. This property has no effect unless the "extended dynamic" property is set to "true". | no |
|
"warning" |
"package library" | Specifies the library for the SQL package. This property has no effect unless the "extended dynamic" property is set to "true". | no | Library for SQL package | "QGPL" |
"prefetch" | Specifies whether to prefetch data upon executing a SELECT statement. This will improve performance when accessing the initial rows in the ResultSet. | no |
|
"true" |
"qaqqinilib" | Specifies a QAQQINI library name. Used to specify the library that contains the qaqqini file to use. A qaqqini file contains all of the attributes that can potentially impact the performance of the DB2? UDB for iSeries? database engine. | no | "QAQQINI library name" | (server default) |
"query optimize goal" |
Specifies the goal the server should use with optimization
of queries. This setting corresponds to the server's QAQQINI option called
OPTIMIZATION_GOAL.
Note: This property is ignored when connecting to systems
running to i5/OS V5R3
and earlier.
|
no |
|
"0" |
Sort properties specify how the server performs stores and performs sorts.
Sort property | Description | Required | Choices | Default |
---|---|---|---|---|
"sort" | Specifies how the server sorts records before sending them to the client. | no |
|
"job" |
"sort language" | Specifies a 3-character language id to use for selection of a sort sequence. This property has no effect unless the "sort" property is set to "language". | no | Language id | ENU |
"sort table" | Specifies the library and file name of a sort sequence table stored on the server. This property has no effect unless the "sort" property is set to "table". | no | Qualified sort table name | "" |
"sort weight" | Specifies how the server treats case while sorting records. This property has no effect unless the "sort" property is set to "language". | no |
|
"shared" |
Other properties are those properties not easily categorized. These properties determine which JDBC driver is used, and specify options related to level of database access, bidirectional string type, data truncation and so on.
Other property | Description | Required | Choices | Default |
---|---|---|---|---|
"access" | Specifies the level of database access for the connection. | no |
|
"all" |
"behavior override" | Specifies which IBM? Toolbox for Java JDBC driver behaviors to override. You can change multiple behaviors in combination by adding the constants and passing that sum on this property. Be sure that your application correctly handles the altered behavior. | no |
|
"" |
"bidi string type" | Specifies the output string type of bidirectional data. See for more information. | no |
|
"" |
"bidi implicit reordering" | Specifies if bidi implicit LTR-RTL reordering should be used. | no |
|
"true" |
"bidi numeric reordering" | Specifies if the numeric ordering round trip feature should be used. | no |
|
"false" |
"data truncation" |
Specifies whether truncation of character data generates attention notices and exceptions. When this property is "true", the following apply:
When this property is "false", writing truncated data to the database or using such data in a query generates no exception or attention notice. The default value is "true". This property does not affect numeric data. Writing truncated numeric data to the database always throws an error and using truncated numeric data in a query always posts attention notices. |
no |
|
"true" |
"driver" | Specifies the JDBC driver implementation. The IBM Toolbox for Java JDBC driver can use different JDBC driver implementations based on the environment. If the environment is an iSeries JVM on the same server as the database to which the program is connecting, the native IBM Developer Kit for Java JDBC driver can be used. In any other environment, the IBM Toolbox for Java JDBC driver is used. This property has no effect if the "secondary URL" property is set. | no |
|
"toolbox" |
"errors" | Specifies the amount of detail to be returned in the message for errors that occur on the server. | no |
|
"basic" |
"extended metadata" |
Specifies whether the driver requests extended metadata from the server.
Setting this property to true increases the accuracy of the information returned
from the following ResultSetMetaData methods:
Additionally, setting this property to true enables support for the ResultSetMetaData.getSchemaName(int) method. Setting this property to true may degrade performance because it requires retrieving more information from the server. Leave the property as the default (false) unless you need more specific information from the listed methods. For example, when this property is off (false), ResultSetMetaData.isSearchable(int) always returns "true" because because the driver does not have enough information from the server to make a judgment. Turning on this property (true) forces the driver to get the correct data from the server. You can use extended metadata only when connecting to a server running i5/OS V5R2 or later. |
no |
|
"false" |
"full open" | Specifies whether the server fully opens a file for each query. By default the server optimizes open requests. This optimization improves performance but may fail if a database monitor is active when a query is run more than once. Set the property to true only when identical queries are issued when monitors are active. | no |
|
"false" |
"hold input locators" | Specifies whether input locators should be allocated as type hold locators or not hold locators. If the locators are of type hold, they will not be released when a commit is done. | no |
|
"true" |
"hold statements" | Specifies if statements should remain open until a transaction boundary when autocommit is off and they are associated with a LOB locator. By default, all the resources associated with a statement are released when the statement is closed. Set this property to true only when access to a LOB locator is needed after a statement has been closed. | no |
|
"false" |
"key ring name" | Specifies the key ring class name used for SSL connections with the server. This property has no effect unless "secure" is set to true and a key ring password is set using the "key ring password" property. | no | "key ring name" | "" |
"key ring password" | Specifies the password for the key ring class used for SSL communications with the server. This property has no effect unless "secure" is set to true and a key ring name is set using the "key ring name" property. | no | "key ring password" | "" |
"proxy server" |
Specifies the host name and port of the middle-tier machine where
the proxy server is running. The format for this is hostname[:port],
where the port is optional. If this is not set, then the hostname and port
are retrieved from the com.ibm.as400.access.AS400.proxyServer property.
The default port is 3470 (if the connection uses SSL, the default
port is 3471). The ProxyServer must be running on the middle-tier
machine.
The name of the middle-tier machine is ignored in a two-tier environment. |
no | Proxy server host name and port | (value of the proxyServer property, or none if not set) |
"remarks" | Specifies the source of the text for REMARKS columns in ResultSets returned by DatabaseMetaData methods. | no |
|
"system" |
"secondary URL" | Specifies the URL to be used for a connection on the middle-tier's DriverManager in a multiple tier environment, if it is different than already specified. This property allows you to use this driver to connect to databases other than the iSeries server. Use a backslash as an escape character before backslashes and semicolons in the URL. | no | JDBC URL | (current JDBC URL) |
"secure" | Specifies whether a Secure Sockets Layer (SSL) connection is used to communicate with the server. SSL connections are only available when connecting to servers at V4R4 or later. | no |
|
"false" |
"server trace" | Specifies the level of tracing of the JDBC server job. When tracing is enabled, tracing starts when the client connects to the server and ends when the connection is disconnected. You must start tracing before connecting to the server, because the client enables server tracing only at connect time. | no |
Multiple types of trace can be started by adding these values together. For example, "6" starts the database monitor and starts debug. |
"0" |
"thread used" | Specifies whether threads are used in communication with the host servers. | no |
|
"true" |
"toolbox trace" | Specifies what category of an IBM Toolbox for Java trace to log. Trace messages are useful for debugging programs that call JDBC. However, there is a performance penalty associated with logging trace messages, so this property is only set for debugging. Trace messages are logged to System.out. | no |
|
"" |
"trace" | Specifies whether trace messages are logged. Trace messages are useful for debugging programs that call JDBC. However, there is a performance penalty associated with logging trace messages, so this property only set to "true" for debugging. Trace messages are logged to System.out. | no |
|
"false" |
"translate binary" | Specifies whether binary data is translated. If this property is set to "true", then BINARY and VARBINARY fields are treated as CHAR and VARCHAR fields. | no |
|
"false" |
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