java.sql: public interface: Connection

java.sql
public interface: Connection [javadoc | source]

All Implemented Interfaces:
Wrapper

A connection (session) with a specific database. SQL statements are executed and results are returned within the context of a connection.

A Connection object's database is able to provide information describing its tables, its supported SQL grammar, its stored procedures, the capabilities of this connection, and so on. This information is obtained with the getMetaData method.

Note: When configuring a Connection, JDBC applications should use the appropritate Connection method such as setAutoCommit or setTransactionIsolation. Applications should not invoke SQL commands directly to change the connection's configuration when there is a JDBC method available. By default a Connection object is in auto-commit mode, which means that it automatically commits changes after executing each statement. If auto-commit mode has been disabled, the method commit must be called explicitly in order to commit changes; otherwise, database changes will not be saved.

A new Connection object created using the JDBC 2.1 core API has an initially empty type map associated with it. A user may enter a custom mapping for a UDT in this type map. When a UDT is retrieved from a data source with the method ResultSet.getObject, the getObject method will check the connection's type map to see if there is an entry for that UDT. If so, the getObject method will map the UDT to the class indicated. If there is no entry, the UDT will be mapped using the standard mapping.

A user may create a new type map, which is a java.util.Map object, make an entry in it, and pass it to the java.sql methods that can perform custom mapping. In this case, the method will use the given type map instead of the one associated with the connection.

For example, the following code fragment specifies that the SQL type ATHLETES will be mapped to the class Athletes in the Java programming language. The code fragment retrieves the type map for the Connection object con, inserts the entry into it, and then sets the type map with the new entry as the connection's type map.

java.util.Map map = con.getTypeMap();
map.put("mySchemaName.ATHLETES", Class.forName("Athletes"));
con.setTypeMap(map);

Also see:

DriverManager#getConnection

Statement

ResultSet

DatabaseMetaData

Field Summary
int	TRANSACTION_NONE	A constant indicating that transactions are not supported.
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.
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.
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").
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.

Method from java.sql.Connection Summary:
clearWarnings, close, commit, createArrayOf, createBlob, createClob, createNClob, createSQLXML, createStatement, createStatement, createStatement, createStruct, getAutoCommit, getCatalog, getClientInfo, getClientInfo, getHoldability, getMetaData, getTransactionIsolation, getTypeMap, getWarnings, isClosed, isReadOnly, isValid, nativeSQL, prepareCall, prepareCall, prepareCall, prepareStatement, prepareStatement, prepareStatement, prepareStatement, prepareStatement, prepareStatement, releaseSavepoint, rollback, rollback, setAutoCommit, setCatalog, setClientInfo, setClientInfo, setHoldability, setReadOnly, setSavepoint, setSavepoint, setTransactionIsolation, setTypeMap

Method from java.sql.Connection Summary:

clearWarnings, close, commit, createArrayOf, createBlob, createClob, createNClob, createSQLXML, createStatement, createStatement, createStatement, createStruct, getAutoCommit, getCatalog, getClientInfo, getClientInfo, getHoldability, getMetaData, getTransactionIsolation, getTypeMap, getWarnings, isClosed, isReadOnly, isValid, nativeSQL, prepareCall, prepareCall, prepareCall, prepareStatement, prepareStatement, prepareStatement, prepareStatement, prepareStatement, prepareStatement, releaseSavepoint, rollback, rollback, setAutoCommit, setCatalog, setClientInfo, setClientInfo, setHoldability, setReadOnly, setSavepoint, setSavepoint, setTransactionIsolation, setTypeMap

Method from java.sql.Connection Detail:
public void clearWarnings() throws SQLException 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.
public void close() throws SQLException 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.
public void commit() throws SQLException 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.
public Array createArrayOf(String typeName, Object[] elements) throws SQLException 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.
public Blob createBlob() throws SQLException 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`.
public Clob createClob() throws SQLException 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`.
public NClob createNClob() throws SQLException 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`.
public SQLXML createSQLXML() throws SQLException 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.
public Statement createStatement() throws SQLException 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 .
public Statement createStatement(int resultSetType, int resultSetConcurrency) throws SQLException 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 .
public Statement createStatement(int resultSetType, int resultSetConcurrency, int resultSetHoldability) throws SQLException 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.
public Struct createStruct(String typeName, Object[] attributes) throws SQLException Factory method for creating Struct objects.
public boolean getAutoCommit() throws SQLException Retrieves the current auto-commit mode for this `Connection` object.
public String getCatalog() throws SQLException Retrieves this `Connection` object's current catalog name.
public Properties getClientInfo() throws SQLException 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.
public String getClientInfo(String name) throws SQLException 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.
public int getHoldability() throws SQLException Retrieves the current holdability of `ResultSet` objects created using this `Connection` object.
public DatabaseMetaData getMetaData() throws SQLException 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.
public int getTransactionIsolation() throws SQLException Retrieves this `Connection` object's current transaction isolation level.
public Map getTypeMap() throws SQLException Retrieves the `Map` object associated with this `Connection` object. Unless the application has added an entry, the type map returned will be empty.
public SQLWarning getWarnings() throws SQLException 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.
public boolean isClosed() throws SQLException 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.
public boolean isReadOnly() throws SQLException Retrieves whether this `Connection` object is in read-only mode.
public boolean isValid(int timeout) throws SQLException 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.
public String nativeSQL(String sql) throws SQLException 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.
public CallableStatement prepareCall(String sql) throws SQLException 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 .
public CallableStatement prepareCall(String sql, int resultSetType, int resultSetConcurrency) throws SQLException 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 .
public CallableStatement prepareCall(String sql, int resultSetType, int resultSetConcurrency, int resultSetHoldability) throws SQLException 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.
public PreparedStatement prepareStatement(String sql) throws SQLException 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 .
public PreparedStatement prepareStatement(String sql, int autoGeneratedKeys) throws SQLException 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 .
public PreparedStatement prepareStatement(String sql, int[] columnIndexes) throws SQLException 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 .
public PreparedStatement prepareStatement(String sql, String[] columnNames) throws SQLException 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 .
public PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency) throws SQLException 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 .
public PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency, int resultSetHoldability) throws SQLException 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.
public void releaseSavepoint(Savepoint savepoint) throws SQLException 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.
public void rollback() throws SQLException 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.
public void rollback(Savepoint savepoint) throws SQLException Undoes all changes made after the given `Savepoint` object was set. This method should be used only when auto-commit has been disabled.
public void setAutoCommit(boolean autoCommit) throws SQLException 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.
public void setCatalog(String catalog) throws SQLException 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.
public void setClientInfo(Properties properties) throws SQLClientInfoException 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.
public void setClientInfo(String name, String value) throws SQLClientInfoException 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.
public void setHoldability(int holdability) throws SQLException 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 .
public void setReadOnly(boolean readOnly) throws SQLException 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.
public Savepoint setSavepoint() throws SQLException 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.
public Savepoint setSavepoint(String name) throws SQLException 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.
public void setTransactionIsolation(int level) throws SQLException 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.
public void setTypeMap(Map map) throws SQLException 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.