Connection

See also:

• DriverManager.getConnection(String)
• Statement
• ResultSet
• DatabaseMetaData

TRANSACTION_NONE

public static final int TRANSACTION_NONE

A constant indicating that transactions are not supported.

Constant Value: 0 (0x00000000)

TRANSACTION_READ_COMMITTED

public static final int TRANSACTION_READ_COMMITTED

A constant indicating that dirty reads are prevented; non-repeatable reads and phantom reads can occur. This level only prohibits a transaction from reading a row with uncommitted changes in it.

Constant Value: 2 (0x00000002)

TRANSACTION_READ_UNCOMMITTED

public static final int TRANSACTION_READ_UNCOMMITTED

A constant indicating that dirty reads, non-repeatable reads and phantom reads can occur. This level allows a row changed by one transaction to be read by another transaction before any changes in that row have been committed (a "dirty read"). If any of the changes are rolled back, the second transaction will have retrieved an invalid row.

Constant Value: 1 (0x00000001)

TRANSACTION_REPEATABLE_READ

public static final int TRANSACTION_REPEATABLE_READ

A constant indicating that dirty reads and non-repeatable reads are prevented; phantom reads can occur. This level prohibits a transaction from reading a row with uncommitted changes in it, and it also prohibits the situation where one transaction reads a row, a second transaction alters the row, and the first transaction rereads the row, getting different values the second time (a "non-repeatable read").

Constant Value: 4 (0x00000004)

TRANSACTION_SERIALIZABLE

public static final int TRANSACTION_SERIALIZABLE

A constant indicating that dirty reads, non-repeatable reads and phantom reads are prevented. This level includes the prohibitions in TRANSACTION_REPEATABLE_READ and further prohibits the situation where one transaction reads all rows that satisfy a WHERE condition, a second transaction inserts a row that satisfies that WHERE condition, and the first transaction rereads for the same condition, retrieving the additional "phantom" row in the second read.

Constant Value: 8 (0x00000008)

clearWarnings

public abstract void clearWarnings ()

Clears all warnings reported for this Connection object. After a call to this method, the method getWarnings returns null until a new warning is reported for this Connection object.

close

public abstract void close ()

Releases this Connection object's database and JDBC resources immediately instead of waiting for them to be automatically released.

Calling the method close on a Connection object that is already closed is a no-op.

It is strongly recommended that an application explicitly commits or rolls back an active transaction prior to calling the close method. If the close method is called and there is an active transaction, the results are implementation-defined.

commit

public abstract void commit ()

Makes all changes made since the previous commit/rollback permanent and releases any database locks currently held by this Connection object. This method should be used only when auto-commit mode has been disabled.

createArrayOf

public abstract Array createArrayOf (String typeName, 
                Object[] elements)

Factory method for creating Array objects.

Note: When createArrayOf is used to create an array object that maps to a primitive data type, then it is implementation-defined whether the Array object is an array of that primitive data type or an array of Object.

Note: The JDBC driver is responsible for mapping the elements Object array to the default JDBC SQL type defined in java.sql.Types for the given class of Object. The default mapping is specified in Appendix B of the JDBC specification. If the resulting JDBC type is not the appropriate type for the given typeName then it is implementation defined whether an SQLException is thrown or the driver supports the resulting conversion.

createBlob

public abstract Blob createBlob ()

Constructs an object that implements the Blob interface. The object returned initially contains no data. The setBinaryStream and setBytes methods of the Blob interface may be used to add data to the Blob.

createClob

public abstract Clob createClob ()

Constructs an object that implements the Clob interface. The object returned initially contains no data. The setAsciiStream, setCharacterStream and setString methods of the Clob interface may be used to add data to the Clob.

createNClob

public abstract NClob createNClob ()

Constructs an object that implements the NClob interface. The object returned initially contains no data. The setAsciiStream, setCharacterStream and setString methods of the NClob interface may be used to add data to the NClob.

createSQLXML

public abstract SQLXML createSQLXML ()

Constructs an object that implements the SQLXML interface. The object returned initially contains no data. The createXmlStreamWriter object and setString method of the SQLXML interface may be used to add data to the SQLXML object.

createStatement

public abstract Statement createStatement (int resultSetType, 
                int resultSetConcurrency)

Creates a Statement object that will generate ResultSet objects with the given type and concurrency. This method is the same as the createStatement method above, but it allows the default result set type and concurrency to be overridden. The holdability of the created result sets can be determined by calling getHoldability().

createStatement

public abstract Statement createStatement ()

Creates a Statement object for sending SQL statements to the database. SQL statements without parameters are normally executed using Statement objects. If the same SQL statement is executed many times, it may be more efficient to use a PreparedStatement object.

Result sets created using the returned Statement object will by default be type TYPE_FORWARD_ONLY and have a concurrency level of CONCUR_READ_ONLY. The holdability of the created result sets can be determined by calling getHoldability().

createStatement

public abstract Statement createStatement (int resultSetType, 
                int resultSetConcurrency, 
                int resultSetHoldability)

Creates a Statement object that will generate ResultSet objects with the given type, concurrency, and holdability. This method is the same as the createStatement method above, but it allows the default result set type, concurrency, and holdability to be overridden.

createStruct

public abstract Struct createStruct (String typeName, 
                Object[] attributes)

Factory method for creating Struct objects.

getAutoCommit

public abstract boolean getAutoCommit ()

Retrieves the current auto-commit mode for this Connection object.

getCatalog

public abstract String getCatalog ()

Retrieves this Connection object's current catalog name.

getClientInfo

public abstract String getClientInfo (String name)

Returns the value of the client info property specified by name. This method may return null if the specified client info property has not been set and does not have a default value. This method will also return null if the specified client info property name is not supported by the driver.

Applications may use the DatabaseMetaData.getClientInfoProperties method to determine the client info properties supported by the driver.

getClientInfo

public abstract Properties getClientInfo ()

Returns a list containing the name and current value of each client info property supported by the driver. The value of a client info property may be null if the property has not been set and does not have a default value.

getHoldability

public abstract int getHoldability ()

Retrieves the current holdability of ResultSet objects created using this Connection object.

getMetaData

public abstract DatabaseMetaData getMetaData ()

Retrieves a DatabaseMetaData object that contains metadata about the database to which this Connection object represents a connection. The metadata includes information about the database's tables, its supported SQL grammar, its stored procedures, the capabilities of this connection, and so on.

getTransactionIsolation

public abstract int getTransactionIsolation ()

Retrieves this Connection object's current transaction isolation level.

getTypeMap

public abstract Map<String, Class<?>> getTypeMap ()

Retrieves the Map object associated with this Connection object. Unless the application has added an entry, the type map returned will be empty.

You must invoke setTypeMap after making changes to the Map object returned from getTypeMap as a JDBC driver may create an internal copy of the Map object passed to setTypeMap:

      Map<String,Class<?>> myMap = con.getTypeMap();
      myMap.put("mySchemaName.ATHLETES", Athletes.class);
      con.setTypeMap(myMap);
 

getWarnings

public abstract SQLWarning getWarnings ()

Retrieves the first warning reported by calls on this Connection object. If there is more than one warning, subsequent warnings will be chained to the first one and can be retrieved by calling the method SQLWarning.getNextWarning on the warning that was retrieved previously.

This method may not be called on a closed connection; doing so will cause an SQLException to be thrown.

Note: Subsequent warnings will be chained to this SQLWarning.

isClosed

public abstract boolean isClosed ()

Retrieves whether this Connection object has been closed. A connection is closed if the method close has been called on it or if certain fatal errors have occurred. This method is guaranteed to return true only when it is called after the method Connection.close has been called.

This method generally cannot be called to determine whether a connection to a database is valid or invalid. A typical client can determine that a connection is invalid by catching any exceptions that might be thrown when an operation is attempted.

isReadOnly

public abstract boolean isReadOnly ()

Retrieves whether this Connection object is in read-only mode.

isValid

public abstract boolean isValid (int timeout)

Returns true if the connection has not been closed and is still valid. The driver shall submit a query on the connection or use some other mechanism that positively verifies the connection is still valid when this method is called.

The query submitted by the driver to validate the connection shall be executed in the context of the current transaction.

nativeSQL

public abstract String nativeSQL (String sql)

Converts the given SQL statement into the system's native SQL grammar. A driver may convert the JDBC SQL grammar into its system's native SQL grammar prior to sending it. This method returns the native form of the statement that the driver would have sent.

prepareCall

public abstract CallableStatement prepareCall (String sql, 
                int resultSetType, 
                int resultSetConcurrency)

Creates a CallableStatement object that will generate ResultSet objects with the given type and concurrency. This method is the same as the prepareCall method above, but it allows the default result set type and concurrency to be overridden. The holdability of the created result sets can be determined by calling getHoldability().

prepareCall

public abstract CallableStatement prepareCall (String sql)

Creates a CallableStatement object for calling database stored procedures. The CallableStatement object provides methods for setting up its IN and OUT parameters, and methods for executing the call to a stored procedure.

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

Result sets created using the returned CallableStatement object will by default be type TYPE_FORWARD_ONLY and have a concurrency level of CONCUR_READ_ONLY. The holdability of the created result sets can be determined by calling getHoldability().

prepareCall

public abstract CallableStatement prepareCall (String sql, 
                int resultSetType, 
                int resultSetConcurrency, 
                int resultSetHoldability)

Creates a CallableStatement object that will generate ResultSet objects with the given type and concurrency. This method is the same as the prepareCall method above, but it allows the default result set type, result set concurrency type and holdability to be overridden.

prepareStatement

public abstract PreparedStatement prepareStatement (String sql, 
                String[] columnNames)

Creates a default PreparedStatement object capable of returning the auto-generated keys designated by the given array. This array contains the names of the columns in the target table that contain the auto-generated keys that should be returned. The driver will ignore the array if the SQL statement is not an INSERT statement, or an SQL statement able to return auto-generated keys (the list of such statements is vendor-specific).

An SQL statement with or without IN parameters can be pre-compiled and stored in a PreparedStatement 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, the method prepareStatement 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 PreparedStatement object is executed. This has no direct effect on users; however, it does affect which methods throw certain SQLExceptions.

Result sets created using the returned PreparedStatement object will by default be type TYPE_FORWARD_ONLY and have a concurrency level of CONCUR_READ_ONLY. The holdability of the created result sets can be determined by calling getHoldability().

prepareStatement

public abstract PreparedStatement prepareStatement (String sql, 
                int resultSetType, 
                int resultSetConcurrency, 
                int resultSetHoldability)

Creates a PreparedStatement object that will generate ResultSet objects with the given type, concurrency, and holdability.

This method is the same as the prepareStatement method above, but it allows the default result set type, concurrency, and holdability to be overridden.

prepareStatement

public abstract PreparedStatement prepareStatement (String sql, 
                int[] columnIndexes)

Creates a default PreparedStatement object capable of returning the auto-generated keys designated by the given array. This array contains the indexes of the columns in the target table that contain the auto-generated keys that should be made available. The driver will ignore the array if the SQL statement is not an INSERT statement, or an SQL statement able to return auto-generated keys (the list of such statements is vendor-specific).

An SQL statement with or without IN parameters can be pre-compiled and stored in a PreparedStatement 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, the method prepareStatement 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 PreparedStatement object is executed. This has no direct effect on users; however, it does affect which methods throw certain SQLExceptions.

Result sets created using the returned PreparedStatement object will by default be type TYPE_FORWARD_ONLY and have a concurrency level of CONCUR_READ_ONLY. The holdability of the created result sets can be determined by calling getHoldability().

prepareStatement

public abstract PreparedStatement prepareStatement (String sql)

Creates a PreparedStatement object for sending parameterized SQL statements to the database.

A SQL statement with or without IN parameters can be pre-compiled and stored in a PreparedStatement 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, the method prepareStatement 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 PreparedStatement object is executed. This has no direct effect on users; however, it does affect which methods throw certain SQLException objects.

Result sets created using the returned PreparedStatement object will by default be type TYPE_FORWARD_ONLY and have a concurrency level of CONCUR_READ_ONLY. The holdability of the created result sets can be determined by calling getHoldability().

prepareStatement

public abstract PreparedStatement prepareStatement (String sql, 
                int autoGeneratedKeys)

Creates a default PreparedStatement object that has the capability to retrieve auto-generated keys. The given constant tells the driver whether it should make auto-generated keys available for retrieval. This parameter is ignored if the SQL statement is not an INSERT statement, or an SQL statement able to return auto-generated keys (the list of such statements is vendor-specific).

Note: This method is optimized for handling parametric SQL statements that benefit from precompilation. If the driver supports precompilation, the method prepareStatement 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 PreparedStatement object is executed. This has no direct effect on users; however, it does affect which methods throw certain SQLExceptions.

Result sets created using the returned PreparedStatement object will by default be type TYPE_FORWARD_ONLY and have a concurrency level of CONCUR_READ_ONLY. The holdability of the created result sets can be determined by calling getHoldability().

prepareStatement

public abstract PreparedStatement prepareStatement (String sql, 
                int resultSetType, 
                int resultSetConcurrency)

Creates a PreparedStatement object that will generate ResultSet objects with the given type and concurrency. This method is the same as the prepareStatement method above, but it allows the default result set type and concurrency to be overridden. The holdability of the created result sets can be determined by calling getHoldability().

releaseSavepoint

public abstract void releaseSavepoint (Savepoint savepoint)

Removes the specified Savepoint and subsequent Savepoint objects from the current transaction. Any reference to the savepoint after it have been removed will cause an SQLException to be thrown.

rollback

public abstract void rollback ()

Undoes all changes made in the current transaction and releases any database locks currently held by this Connection object. This method should be used only when auto-commit mode has been disabled.

rollback

public abstract void rollback (Savepoint savepoint)

Undoes all changes made after the given Savepoint object was set.

This method should be used only when auto-commit has been disabled.

setAutoCommit

public abstract void setAutoCommit (boolean autoCommit)

Sets this connection's auto-commit mode to the given state. 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 a call to either the method commit or the method rollback. By default, new connections are in auto-commit mode.

The commit occurs when the statement completes. The time when the statement completes depends on the type of SQL Statement:

• For DML statements, such as Insert, Update or Delete, and DDL statements, the statement is complete as soon as it has finished executing.
• For Select statements, the statement is complete when the associated result set is closed.
• For CallableStatement objects or for statements that return multiple results, the statement is complete when all of the associated result sets have been closed, and all update counts and output parameters have been retrieved.

NOTE: If this method is called during a transaction and the auto-commit mode is changed, the transaction is committed. If setAutoCommit is called and the auto-commit mode is not changed, the call is a no-op.

setCatalog

public abstract void setCatalog (String catalog)

Sets the given catalog name in order to select a subspace of this Connection object's database in which to work.

If the driver does not support catalogs, it will silently ignore this request.

Calling setCatalog has no effect on previously created or prepared Statement objects. It is implementation defined whether a DBMS prepare operation takes place immediately when the Connection method prepareStatement or prepareCall is invoked. For maximum portability, setCatalog should be called before a Statement is created or prepared.

setClientInfo

public abstract void setClientInfo (Properties properties)

Sets the value of the connection's client info properties. The Properties object contains the names and values of the client info properties to be set. The set of client info properties contained in the properties list replaces the current set of client info properties on the connection. If a property that is currently set on the connection is not present in the properties list, that property is cleared. Specifying an empty properties list will clear all of the properties on the connection. See setClientInfo (String, String) for more information.

If an error occurs in setting any of the client info properties, a SQLClientInfoException is thrown. The SQLClientInfoException contains information indicating which client info properties were not set. The state of the client information is unknown because some databases do not allow multiple client info properties to be set atomically. For those databases, one or more properties may have been set before the error occurred.

setClientInfo

public abstract void setClientInfo (String name, 
                String value)

Sets the value of the client info property specified by name to the value specified by value.

Applications may use the DatabaseMetaData.getClientInfoProperties method to determine the client info properties supported by the driver and the maximum length that may be specified for each property.

The driver stores the value specified in a suitable location in the database. For example in a special register, session parameter, or system table column. For efficiency the driver may defer setting the value in the database until the next time a statement is executed or prepared. Other than storing the client information in the appropriate place in the database, these methods shall not alter the behavior of the connection in anyway. The values supplied to these methods are used for accounting, diagnostics and debugging purposes only.

The driver shall generate a warning if the client info name specified is not recognized by the driver.

If the value specified to this method is greater than the maximum length for the property the driver may either truncate the value and generate a warning or generate a SQLClientInfoException. If the driver generates a SQLClientInfoException, the value specified was not set on the connection.

The following are standard client info properties. Drivers are not required to support these properties however if the driver supports a client info property that can be described by one of the standard properties, the standard property name should be used.

• ApplicationName - The name of the application currently utilizing the connection
• ClientUser - The name of the user that the application using the connection is performing work for. This may not be the same as the user name that was used in establishing the connection.
• ClientHostname - The hostname of the computer the application using the connection is running on.

setHoldability

public abstract void setHoldability (int holdability)

Changes the default holdability of ResultSet objects created using this Connection object to the given holdability. The default holdability of ResultSet objects can be be determined by invoking DatabaseMetaData#getResultSetHoldability.

setReadOnly

public abstract void setReadOnly (boolean readOnly)

Puts this connection in read-only mode as a hint to the driver to enable database optimizations.

Note: This method cannot be called during a transaction.

setSavepoint

public abstract Savepoint setSavepoint (String name)

Creates a savepoint with the given name in the current transaction and returns the new Savepoint object that represents it.

if setSavepoint is invoked outside of an active transaction, a transaction will be started at this newly created savepoint.

setSavepoint

public abstract Savepoint setSavepoint ()

Creates an unnamed savepoint in the current transaction and returns the new Savepoint object that represents it.

if setSavepoint is invoked outside of an active transaction, a transaction will be started at this newly created savepoint.

setTransactionIsolation

public abstract void setTransactionIsolation (int level)

Attempts to change the transaction isolation level for this Connection object to the one given. The constants defined in the interface Connection are the possible transaction isolation levels.

Note: If this method is called during a transaction, the result is implementation-defined.

setTypeMap

public abstract void setTypeMap (Map<String, Class<?>> map)

Installs the given TypeMap object as the type map for this Connection object. The type map will be used for the custom mapping of SQL structured types and distinct types.

You must set the the values for the TypeMap prior to callng setMap as a JDBC driver may create an internal copy of the TypeMap:

      Map myMap<String,Class<?>> = new HashMap<String,Class<?>>();
      myMap.put("mySchemaName.ATHLETES", Athletes.class);
      con.setTypeMap(myMap);