ModSQL
Interface DatabaseManager

All Known Implementing Classes:

MetaManager, Manager, Manager, Manager

public interface DatabaseManager

Interface to be implemented by database managers.

To create a new type of database, you need to implement both this interface and the DatabaseTable interface. The primary role of the DatabaseManager is to create DatabaseTable objects when given a table name.

Author:

chris.studholme@utoronto.ca

See Also:

DatabaseTable

Method Summary

boolean	createIndex(String tablename, String columnname) Create an index of the specified column in the specified table (if capable).
DatabaseTable	createTable(String tablename, boolean temporary) Create a new table.
boolean	dropIndex(String tablename, String columnname) Drop an index.
void	dropTable(String tablename) Drop a table.
Function	getFunction(String name) Get a database specific function for use in SQL.
int	getMajorVersion() Get the driver's major version number.
int	getMinorVersion() Get the driver's minor version number.
boolean	hasTable(String tablename) Checks whether this database has the specified table.
DatabaseTable	openTable(String tablename) Opens the database table with the specified name for read only access.
DatabaseTable	openTable(String tablename, boolean readonly) Opens the database table with the specified name with read only or read write access.

Method Detail

getMajorVersion

public int getMajorVersion()

Get the driver's major version number. Initially this should be 1.

Returns:

major version number

getMinorVersion

public int getMinorVersion()

Get the driver's minor version number. Initially this should be 0.

Returns:

minor version number

hasTable

public boolean hasTable(String tablename)
                 throws DatabaseException

Checks whether this database has the specified table.

Parameters:

tablename - name of the table

Returns:

true if the table exists in this database and can be opened, false otherwise

Throws:

DatabaseException - if a database-access error occurs

openTable

public DatabaseTable openTable(String tablename)
                        throws DatabaseException

Opens the database table with the specified name for read only access.

Parameters:

tablename - name of the table to open

Returns:

a DatabaseTable object representing the table, or null if the table does not exist in this database

Throws:

DatabaseException - if a database-access error occurs

openTable

public DatabaseTable openTable(String tablename,
                               boolean readonly)
                        throws DatabaseException

Opens the database table with the specified name with read only or read write access.

Parameters:

tablename - name of the table to open

readonly - true to open table read only

Returns:

a DatabaseTable object representing the table, or null if the table does not exist in this database

Throws:

DatabaseException - if a database-access error occurs

createTable

public DatabaseTable createTable(String tablename,
                                 boolean temporary)
                          throws DatabaseException

Create a new table. If a table with the given name exists in the database, this method should always throw an exception. If the database is not capable of supporting user created tables, this method should return null.

Parameters:

tablename - name of the table to create

temporary - table is temporary

Returns:

the newly created table opened for read write access, or null if the database doesn't support creating tables

Throws:

DatabaseException - if a database-access error occurs

createIndex

public boolean createIndex(String tablename,
                           String columnname)
                    throws DatabaseException

Create an index of the specified column in the specified table (if capable).

Parameters:

tablename - name of the table to index

columnname - name of the column to index

Returns:

true if index was created, false if database is not capable of creating indicies

Throws:

DatabaseException - if a database-access error occurs

dropTable

public void dropTable(String tablename)
               throws DatabaseException

Drop a table. This method should throw an exception if the table does not exist.

Parameters:

tablename - name of the table to drop

Throws:

DatabaseException - if a database-access error occurs

dropIndex

public boolean dropIndex(String tablename,
                         String columnname)
                  throws DatabaseException

Drop an index. This method should throw an exception if the table does not exist, but should return false if the column has not been indexed.

Parameters:

tablename - name of the table with index

columnname - name of the column with index

Returns:

true if the index existed and has been dropped, false if it didn't exist

Throws:

DatabaseException - if a database-access error occurs

getFunction

public Function getFunction(String name)
                     throws DatabaseException

Get a database specific function for use in SQL. This function may be used in any SQL query (not just queries involving this database's tables). Note that when looking up function names, ModSQL will always check for database specific functions before using built-in functions, so this method may be used to override the built-in SQL functions.

This method should return null if a function by the specified name is not found.

Parameters:

name - name of function to lookup (always lowercase)

Returns:

new function object (or null if function not found)

Throws:

DatabaseException - if a database-access error occurs