oracle.ifs.share.sql

Class ConnectionWrapper

java.lang.Object

oracle.ifs.share.sql.ConnectionWrapper

Direct Known Subclasses:

IfsConnection

public class ConnectionWrapper
extends Object

An ConnectionWrapper represents a session with a specific database. Within the context of an ConnectionWrapper, SQL statements are executed and results are returned.

Author:

Dave Long

(Published)

Constructor Summary

Constructors

Constructor and Description
ConnectionWrapper() Constructs a ConnectionWrapper.
ConnectionWrapper(Connection conn) Constructs a ConnectionWrapper.

Method Summary

Modifier and Type	Method and Description
void	clearWarnings() After this call, getWarnings returns null until a new warning is reported for this ConnectionWrapper.
void	commit() Commit makes all changes made since the previous commit/rollback permanent and releases any database locks currently held by the ConnectionWrapper.
protected CallableStatementWrapper	constructCallableStatementWrapper(CallableStatement cstmt) Constructs a CallableStatementWrapper.
protected PreparedStatementWrapper	constructPreparedStatementWrapper(PreparedStatement pstmt) Constructs a PreparedStatementWrapper.
protected StatementWrapper	constructStatementWrapper(Statement stmt) Constructs a StatementWrapper.
StatementWrapper	createStatement() Create a statement.
void	dispose() Dispose the ConnectionWrapper and any IfsStatement objects.
boolean	execute(PreparedStatement pstmt) Some prepared statements return multiple results; the execute method handles these complex statements as well as the simpler form of statements handled by executeQuery and executeUpdate.
boolean	execute(Statement stmt, String sql) Execute a SQL statement that may return multiple results.
int[]	executeBatch(Statement stmt) Submits a batch of commands to the database for execution and if all commands execute successfully, returns an array of update counts.
ResultSet	executeQuery(PreparedStatement pstmt) A prepared SQL query is executed and its ResultSet is returned.
ResultSet	executeQuery(Statement stmt, String sql) Execute a SQL statement that returns a single ResultSet.
int	executeUpdate(PreparedStatement pstmt) Execute a SQL INSERT, UPDATE or DELETE statement.
int	executeUpdate(Statement stmt, String sql) Execute a SQL INSERT, UPDATE or DELETE statement.
boolean	getAutoCommit() Get the current auto-commit state.
String	getCatalog() Return the ConnectionWrapper's current catalog name.
DatabaseMetaData	getMetaData() An ConnectionWrapper's database is able to provide information describing its tables, its supported SQL grammar, its stored procedures, the capabilities of this connection, etc.
int	getTransactionIsolation() Get this ConnectionWrapper's current transaction isolation mode.
SQLWarning	getWarnings() The first warning reported by calls on this ConnectionWrapper is returned.
protected void	initialize(Connection conn) Initializes a ConnectionWrapper.
boolean	isClosed() Tests to see if an ConnectionWrapper is closed.
boolean	isReadOnly() Tests to see if the connection is in read-only mode.
String	nativeSQL(String sql) A driver may convert the JDBC sql grammar into its system's native SQL grammar prior to sending it; nativeSQL returns the native form of the statement that the driver would have sent.
CallableStatementWrapper	prepareCall(String sql) Create a callable statement, used for stored procedures.
PreparedStatementWrapper	prepareStatement(String sql) Create a prepared statement.
void	rollback() Rollback drops all changes made since the previous commit/rollback and releases any database locks currently held by the ConnectionWrapper.
void	setAutoCommit(boolean autoCommit) If a connection is in auto-commit mode, then all its SQL statements will be executed and committed as individual transactions.
void	setCatalog(String catalog) A sub-space of this ConnectionWrapper's database may be selected by setting a catalog name.
void	setReadOnly(boolean readOnly) You can put a connection in read-only mode as a hint to enable database optimizations.
void	setTransactionIsolation(int level) You can call this method to try to change the transaction isolation level using one of the TRANSACTION_* values.

Methods inherited from class java.lang.Object

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

Constructor Detail

ConnectionWrapper

public ConnectionWrapper()

Constructs a ConnectionWrapper.

(Unpublished)

ConnectionWrapper

public ConnectionWrapper(Connection conn)

Constructs a ConnectionWrapper.

Parameters:

conn - JDBC connection

(Published)

Method Detail

initialize

protected void initialize(Connection conn)

Initializes a ConnectionWrapper.

Parameters:

conn - JDBC connection

(Unpublished)

createStatement

public StatementWrapper createStatement()
                                 throws SQLException

Create a statement.

SQL statements without parameters are normally executed using StatementWrapper objects. If the same SQL statement is executed many times, it is more efficient to use a PreparedStatementWrapper.

Returns:

a new StatementWrapper object

Throws:

SQLException - if a database-access error occurs.

(Published)

prepareStatement

public PreparedStatementWrapper prepareStatement(String sql)
                                          throws SQLException

Create a prepared statement.

A SQL statement with or without IN parameters can be pre-compiled and stored in an IfsPreparedStatement object. This object can then be used to efficiently execute this statement multiple times.

Note: This method is optimized for handling parametric SQL statements that benefit from precompilation. If the driver supports precompilation, this method will send the statement to the database for precompilation. Some drivers may not support precompilation. In this case, the statement may not be sent to the database until the IfsPreparedStatement is executed. This has no direct affect on users; however, it does affect which method throws certain SQLExceptions.

Parameters:

sql - a SQL statement that may contain one or more '?' IN parameter placeholders

Returns:

a new IfsPreparedStatement object containing the pre-compiled statement

Throws:

SQLException - if a database-access error occurs.

(Published)

prepareCall

public CallableStatementWrapper prepareCall(String sql)
                                     throws SQLException

Create a callable statement, used for stored procedures.

A SQL stored procedure call statement is handled by creating a IfsCallableStatement for it. The IfsCallableStatement provides methods for setting up its IN and OUT parameters, and methods for executing it.

Note: This method is optimized for handling stored procedure call statements. Some drivers may send the call statement to the database when the prepareCall is done; others may wait until the IfsCallableStatement is executed. This has no direct affect on users; however, it does affect which method throws certain SQLExceptions.

Parameters:

sql - a SQL statement that may contain one or more '?' parameter placeholders. Typically this statement is a JDBC function call escape string.

Returns:

a new IfsCallableStatement object containing the pre-compiled SQL statement

Throws:

SQLException - if a database-access error occurs.

(Published)

constructStatementWrapper

protected StatementWrapper constructStatementWrapper(Statement stmt)

Constructs a StatementWrapper.

This can be overridden to construct a subclass of StatementWrapper.

Parameters:

stmt - the Statement to wrap

Returns:

a new StatementWrapper

(Unpublished)

constructPreparedStatementWrapper

protected PreparedStatementWrapper constructPreparedStatementWrapper(PreparedStatement pstmt)

Constructs a PreparedStatementWrapper.

This can be overridden to construct a subclass of PreparedStatementWrapper.

Parameters:

pstmt - the PreparedStatement to wrap

Returns:

a new PreparedStatementWrapper

(Unpublished)

constructCallableStatementWrapper

protected CallableStatementWrapper constructCallableStatementWrapper(CallableStatement cstmt)

Constructs a CallableStatementWrapper.

This can be overridden to construct a subclass of CallableStatement.

Parameters:

cstmt - the CallableStatement to wrap

Returns:

a new CallableStatementWrapper

(Unpublished)

executeQuery

public ResultSet executeQuery(Statement stmt,
                              String sql)
                       throws SQLException

Execute a SQL statement that returns a single ResultSet.

Parameters:

stmt - the Statement

sql - typically this is a static SQL SELECT statement

Returns:

a ResultSet that contains the data produced by the query; never null

Throws:

SQLException - if a database-access error occurs.

(Published)

executeUpdate

public int executeUpdate(Statement stmt,
                         String sql)
                  throws SQLException

Execute a SQL INSERT, UPDATE or DELETE statement. Although SQL DDL statements can be executed, it is not advised since doing so can cause the iFS repository to be non-functional or irreparable.

Parameters:

stmt - the Statement

sql - a SQL INSERT, UPDATE or DELETE statement or a SQL statement that returns nothing

Returns:

either the row count for INSERT, UPDATE or DELETE or 0 for SQL statements that return nothing

Throws:

SQLException - if a database-access error occurs.

(Published)

execute

public boolean execute(Statement stmt,
                       String sql)
                throws SQLException

Execute a SQL statement that may return multiple results. Under some (uncommon) situations a single SQL statement may return multiple result sets and/or update counts. Normally you can ignore this, unless you're executing a stored procedure that you know may return multiple results, or unless you're dynamically executing an unknown SQL string. The "execute", "getMoreResults", "getResultSet" and "getUpdateCount" methods let you navigate through multiple results. The "execute" method executes a SQL statement and indicates the form of the first result. You can then use getResultSet or getUpdateCount to retrieve the result, and getMoreResults to move to any subsequent result(s).

Parameters:

stmt - any SQL statement

sql - the SQL string

Returns:

true if the next result is a ResultSet; false if it is an update count or there are no more results

Throws:

SQLException - if a database-access error occurs.

(Published)

executeBatch

public int[] executeBatch(Statement stmt)
                   throws SQLException

Submits a batch of commands to the database for execution and if all commands execute successfully, returns an array of update counts.

Parameters:

stmt - any SQL statement

Returns:

an array of update counts containing one element for each command in the batch. The elements of the array are ordered according to the order in which commands were added to the batch

Throws:

SQLException - if a database-access error occurs.

(Published)

executeQuery

public ResultSet executeQuery(PreparedStatement pstmt)
                       throws SQLException

A prepared SQL query is executed and its ResultSet is returned.

Parameters:

pstmt - the SQL statement

Returns:

a ResultSet that contains the data produced by the query; never null

Throws:

SQLException - if a database-access error occurs.

(Published)

executeUpdate

public int executeUpdate(PreparedStatement pstmt)
                  throws SQLException

Execute a SQL INSERT, UPDATE or DELETE statement. Although SQL DDL statements can be executed, it is not advised since doing so can cause the iFS repository to be non-functional or irreparable.

Parameters:

pstmt - the SQL statement

Returns:

either the row count for INSERT, UPDATE or DELETE; or 0 for SQL statements that return nothing

Throws:

SQLException - if a database-access error occurs.

(Published)

execute

public boolean execute(PreparedStatement pstmt)
                throws SQLException

Some prepared statements return multiple results; the execute method handles these complex statements as well as the simpler form of statements handled by executeQuery and executeUpdate.

Parameters:

pstmt - the SQL statement

Returns:

execution status

Throws:

SQLException - if a database-access error occurs.

(Published)

nativeSQL

public String nativeSQL(String sql)
                 throws SQLException

A driver may convert the JDBC sql grammar into its system's native SQL grammar prior to sending it; nativeSQL returns the native form of the statement that the driver would have sent.

Parameters:

sql - a SQL statement that may contain one or more '?' parameter placeholders

Returns:

the native form of this statement

Throws:

SQLException - if a database-access error occurs.

(Published)

setAutoCommit

public void setAutoCommit(boolean autoCommit)
                   throws SQLException

If a connection is in auto-commit mode, then all its SQL statements will be executed and committed as individual transactions. Otherwise, its SQL statements are grouped into transactions that are terminated by either commit() or rollback(). By default, new connections are in auto-commit mode. The commit occurs when the statement completes or the next execute occurs, whichever comes first. In the case of statements returning a ResultSet, the statement completes when the last row of the ResultSet has been retrieved or the ResultSet has been closed. In advanced cases, a single statement may return multiple results as well as output parameter values. Here the commit occurs when all results and output param values have been retrieved.

Parameters:

autoCommit - true enables auto-commit; false disables auto-commit.

Throws:

SQLException - if a database-access error occurs.

(Unpublished)

getAutoCommit

public boolean getAutoCommit()
                      throws SQLException

Get the current auto-commit state.

Returns:

Current state of auto-commit mode.

Throws:

SQLException - if a database-access error occurs.

(Published)

commit

public void commit()
            throws SQLException

Commit makes all changes made since the previous commit/rollback permanent and releases any database locks currently held by the ConnectionWrapper. This method should only be used when auto commit has been disabled.

Throws:

SQLException - if a database-access error occurs.

(Unpublished)

rollback

public void rollback()
              throws SQLException

Rollback drops all changes made since the previous commit/rollback and releases any database locks currently held by the ConnectionWrapper. This method should only be used when auto commit has been disabled.

Throws:

SQLException - if a database-access error occurs.

(Unpublished)

isClosed

public boolean isClosed()
                 throws SQLException

Tests to see if an ConnectionWrapper is closed.

Returns:

true if the connection is closed; false if still open

Throws:

SQLException - if a database-access error occurs.

(Published)

getMetaData

public DatabaseMetaData getMetaData()
                             throws SQLException

An ConnectionWrapper's database is able to provide information describing its tables, its supported SQL grammar, its stored procedures, the capabilities of this connection, etc. This information is made available through a DatabaseMetaData object.

Returns:

a DatabaseMetaData object for this ConnectionWrapper

Throws:

SQLException - if a database-access error occurs.

(Published)

setReadOnly

public void setReadOnly(boolean readOnly)
                 throws SQLException

You can put a connection in read-only mode as a hint to enable database optimizations.

Note: setReadOnly cannot be called while in the middle of a transaction.

Parameters:

readOnly - true enables read-only mode; false disables read-only mode.

Throws:

SQLException - if a database-access error occurs.

(Unpublished)

isReadOnly

public boolean isReadOnly()
                   throws SQLException

Tests to see if the connection is in read-only mode.

Returns:

true if connection is read-only

Throws:

SQLException - if a database-access error occurs.

(Published)

setCatalog

public void setCatalog(String catalog)
                throws SQLException

A sub-space of this ConnectionWrapper's database may be selected by setting a catalog name. If the driver does not support catalogs it will silently ignore this request.

Parameters:

catalog - tthe catalog name

Throws:

SQLException - if a database-access error occurs.

(Unpublished)

getCatalog

public String getCatalog()
                  throws SQLException

Return the ConnectionWrapper's current catalog name.

Returns:

the current catalog name or null

Throws:

SQLException - if a database-access error occurs.

(Published)

setTransactionIsolation

public void setTransactionIsolation(int level)
                             throws SQLException

You can call this method to try to change the transaction isolation level using one of the TRANSACTION_* values.

Note: setTransactionIsolation cannot be called while in the middle of a transaction.

Parameters:

level - one of the TRANSACTION_* isolation values with the exception of TRANSACTION_NONE; some databases may not support other values

Throws:

SQLException - if a database-access error occurs.

(Unpublished)

getTransactionIsolation

public int getTransactionIsolation()
                            throws SQLException

Get this ConnectionWrapper's current transaction isolation mode.

Returns:

the current TRANSACTION_* mode value

Throws:

SQLException - if a database-access error occurs.

(Published)

getWarnings

public SQLWarning getWarnings()
                       throws SQLException

The first warning reported by calls on this ConnectionWrapper is returned.

Note: Subsequent warnings will be chained to this SQLWarning.

Returns:

the first SQLWarning or null

Throws:

SQLException - if a database-access error occurs.

(Published)

clearWarnings

public void clearWarnings()
                   throws SQLException

After this call, getWarnings returns null until a new warning is reported for this ConnectionWrapper.

Throws:

SQLException - if a database-access error occurs.

(Published)

dispose

public void dispose()
             throws SQLException

Dispose the ConnectionWrapper and any IfsStatement objects.

Throws:

SQLException - if the operation fails

(Unpublished)