Class Database

java.lang.Object
com.mckoi.database.Database
All Implemented Interfaces:
DatabaseConstants

public final class Database extends Object implements DatabaseConstants
The representation of a single database in the system. A database is a set of schema, a set of tables and table definitions of tables in the schema, and a description of the schema.

This class encapsulates the top level behaviour of a database. That is of creating itself, initializing itself, shutting itself down, deleting itself, creating/dropping a table, updating a table. It is not the responsibility of this class to handle table behaviour above this. Top level table behaviour is handled by DataTable through the DatabaseConnection interface.

The Database object is also responsible for various database management functions such a creating, editing and removing users, triggers, functions and services.

Author:
Tobias Downer
  • Field Details

    • SYSTEM_SCHEMA

      public static final String SYSTEM_SCHEMA
      The name of the system schema that contains tables refering to system information.
      See Also:
    • DEFAULT_SCHEMA

      public static final String DEFAULT_SCHEMA
      The name of the default schema.
      See Also:
    • JDBC_SCHEMA

      public static final String JDBC_SCHEMA
      The name of the schema that contains JDBC helper tables.
      See Also:
    • SYS_PASSWORD

      public static final TableName SYS_PASSWORD
      The password privs and grants table.
    • SYS_USERCONNECT

      public static final TableName SYS_USERCONNECT
    • SYS_USERPRIV

      public static final TableName SYS_USERPRIV
    • SYS_GRANTS

      public static final TableName SYS_GRANTS
    • SYS_SERVICE

      public static final TableName SYS_SERVICE
      The services table.
    • SYS_FUNCTIONFACTORY

      public static final TableName SYS_FUNCTIONFACTORY
      The function factory table.
    • SYS_FUNCTION

      public static final TableName SYS_FUNCTION
      The function table.
    • SYS_VIEW

      public static final TableName SYS_VIEW
      The view table.
    • SYS_LABEL

      public static final TableName SYS_LABEL
      The label table.
    • SYS_TABLE_COLUMNS

      public static final TableName SYS_TABLE_COLUMNS
      The system internally generated 'sUSRTableColumns' table.
    • SYS_TABLE_INFO

      public static final TableName SYS_TABLE_INFO
      The system internally generated 'sUSRTableInfo' table.
    • SYS_DATA_TRIGGER

      public static final TableName SYS_DATA_TRIGGER
      The system internally generated 'sUSRDataTrigger' table.
    • SYS_DB_STATISTICS

      public static final TableName SYS_DB_STATISTICS
      The system internally generated 'sUSRDatabaseStatistics' table.
    • OLD_TRIGGER_TABLE

      public static final TableName OLD_TRIGGER_TABLE
      The OLD table used inside a triggered procedure to represent a triggered row before the operation occurs.
    • NEW_TRIGGER_TABLE

      public static final TableName NEW_TRIGGER_TABLE
      The NEW table used inside a triggered procedure to represent a triggered row after the operation occurs.
    • LOCK_GROUP

      public static final String LOCK_GROUP
      The name of the lock group. If a user belongs to this group the user account is locked and they are not allowed to log into the database.
      See Also:
    • SECURE_GROUP

      public static final String SECURE_GROUP
      THe name of the secure access group. If a user belongs to this group they are permitted to perform a number of priviledged operations such as shutting down the database, and adding and removing users.
      See Also:
    • USER_MANAGER_GROUP

      public static final String USER_MANAGER_GROUP
      The name of the user manager group. Users that belong in this group can create, alter and drop users from the system.
      See Also:
    • SCHEMA_MANAGER_GROUP

      public static final String SCHEMA_MANAGER_GROUP
      The name of the schema manager group. Users that belong in this group can create and drop schema from the system.
      See Also:
    • INTERNAL_SECURE_USERNAME

      public static final String INTERNAL_SECURE_USERNAME
      The username of the internal secure user. The internal secure user is only used for internal highly privileged operations. This user is given full privs to everything and is used to manage the system tables, for authentication, etc.
      See Also:
  • Constructor Details

    • Database

      public Database(DatabaseSystem system, String name)
      The Constructor. This takes a directory path in which the database is stored.
  • Method Details

    • getName

      public String getName()
      Returns the name of this database.
    • isReadOnly

      public boolean isReadOnly()
      Returns true if this database is in read only mode.
    • getCommandsLog

      public Log getCommandsLog()
      Returns the log file where commands are recorded.
    • createNewConnection

      public DatabaseConnection createNewConnection(User user, DatabaseConnection.CallBack call_back)
      Returns a new DatabaseConnection instance that is used against this database.

      When a new connection is made on this database, this method is called to create a new DatabaseConnection instance for the connection. This connection handles all transactional queries and modifications to the database.

    • authenticateUser

      public User authenticateUser(String username, String password, String connection_string)
      Tries to authenticate a username/password against this database. If we fail to authenticate then a 'null' object is returned, otherwise a valid User object is returned. If a valid object is returned, the user will be logged into the engine via the UserManager object (in DatabaseSystem). The developer must ensure that 'close' is called before the object is disposed (logs out of the system).

      This method also returns null if a user exists but was denied access from the given host string. The given 'host_name' object is formatted in the database host connection encoding. This method checks all the values from the sUSRUserConnectPriv table for this user for the given protocol. It first checks if the user is specifically DENIED access from the given host. It then checks if the user is ALLOWED access from the given host. If a host is neither allowed or denied then it is denied.

    • userExists

      public boolean userExists(DatabaseQueryContext context, String username) throws DatabaseException
      Returns true if a user exists in this database, otherwise returns false.

      NOTE: Assumes exclusive lock on DatabaseConnection.

      Throws:
      DatabaseException
    • createUser

      public void createUser(DatabaseQueryContext context, String username, String password) throws DatabaseException
      Creates and adds a new user to this database. The User object for the user is returned.

      If the user is already defined by the database then an error is generated.

      NOTE: Assumes exclusive lock on DatabaseConnection.

      Throws:
      DatabaseException
    • deleteAllUserGroups

      public void deleteAllUserGroups(DatabaseQueryContext context, String username) throws DatabaseException
      Deletes all the groups the user belongs to. This is intended for a user alter command for setting the groups a user belongs to.

      NOTE: Assumes exclusive lock on DatabaseConnection.

      Throws:
      DatabaseException
    • deleteUser

      public void deleteUser(DatabaseQueryContext context, String username) throws DatabaseException
      Deletes the user from the system. This also deletes all information associated with a user such as the groups they belong to. It does not delete the privs a user has set up.

      NOTE: Assumes exclusive lock on DatabaseConnection.

      Throws:
      DatabaseException
    • alterUserPassword

      public void alterUserPassword(DatabaseQueryContext context, String username, String password) throws DatabaseException
      Alters the password of the user but otherwise does not change any information about the user.

      NOTE: Assumes exclusive lock on DatabaseConnection.

      Throws:
      DatabaseException
    • groupsUserBelongsTo

      public String[] groupsUserBelongsTo(DatabaseQueryContext context, String username) throws DatabaseException
      Returns the list of all user groups the user belongs to.
      Throws:
      DatabaseException
    • userBelongsToGroup

      public boolean userBelongsToGroup(DatabaseQueryContext context, String username, String group) throws DatabaseException
      Returns true if the given user belongs to the given group otherwise returns false.

      NOTE: Assumes exclusive lock on DatabaseConnection.

      Throws:
      DatabaseException
    • addUserToGroup

      public void addUserToGroup(DatabaseQueryContext context, String username, String group) throws DatabaseException
      Adds the user to the given group. This makes an entry in the sUSRUserPriv for this user and the given group. If the user already belongs to the group then no changes are made.

      It is important that any security checks for ensuring the grantee is allowed to give the user these privs are preformed before this method is called.

      NOTE: Assumes exclusive lock on DatabaseConnection.

      Throws:
      DatabaseException
    • setUserLock

      public void setUserLock(DatabaseQueryContext context, User user, boolean lock_status) throws DatabaseException
      Sets the lock status for the given user. If a user account if locked, it is rejected from logging in to the database.

      It is important that any security checks to determine if the process setting the user lock is allowed to do it is done before this method is called.

      NOTE: Assumes exclusive lock on DatabaseConnection.

      Throws:
      DatabaseException
    • grantHostAccessToUser

      public void grantHostAccessToUser(DatabaseQueryContext context, String user, String protocol, String host) throws DatabaseException
      Grants the given user access to connect to the database from the given host address. The 'protocol' string is the connecting protocol which can be either 'TCP' or 'Local'. The 'host' string is the actual host that is connecting. For example, if the protocol was TCP then the client host may be '127.0.0.1' for localhost.
      Throws:
      DatabaseException
    • canUserCreateAndDropUsers

      public boolean canUserCreateAndDropUsers(DatabaseQueryContext context, User user) throws DatabaseException
      Returns true if the user is permitted to create, alter and drop user information from the database, otherwise returns false. Only members of the 'secure access' group, or the 'user manager' group can do this.
      Throws:
      DatabaseException
    • canUserCreateAndDropSchema

      public boolean canUserCreateAndDropSchema(DatabaseQueryContext context, User user, String schema) throws DatabaseException
      Returns true if the user is permitted to create and drop schema's in the database, otherwise returns false. Only members of the 'secure access' group, or the 'schema manager' group can do this.
      Throws:
      DatabaseException
    • canUserShutDown

      public boolean canUserShutDown(DatabaseQueryContext context, User user) throws DatabaseException
      Returns true if the user can shut down the database server. A user can shut down the database if they are a member of the 'secure acces' group.
      Throws:
      DatabaseException
    • canUserExecuteStoredProcedure

      public boolean canUserExecuteStoredProcedure(DatabaseQueryContext context, User user, String procedure_name) throws DatabaseException
      Returns true if the user is allowed to execute the given stored procedure.
      Throws:
      DatabaseException
    • canUserCreateTableObject

      public boolean canUserCreateTableObject(DatabaseQueryContext context, User user, TableName table) throws DatabaseException
      Returns true if the user can create a table or view with the given name, otherwise returns false.
      Throws:
      DatabaseException
    • canUserAlterTableObject

      public boolean canUserAlterTableObject(DatabaseQueryContext context, User user, TableName table) throws DatabaseException
      Returns true if the user can alter a table or view with the given name, otherwise returns false.
      Throws:
      DatabaseException
    • canUserDropTableObject

      public boolean canUserDropTableObject(DatabaseQueryContext context, User user, TableName table) throws DatabaseException
      Returns true if the user can drop a table or view with the given name, otherwise returns false.
      Throws:
      DatabaseException
    • canUserSelectFromTableObject

      public boolean canUserSelectFromTableObject(DatabaseQueryContext context, User user, TableName table, Variable[] columns) throws DatabaseException
      Returns true if the user can select from a table or view with the given name and given columns, otherwise returns false.
      Throws:
      DatabaseException
    • canUserInsertIntoTableObject

      public boolean canUserInsertIntoTableObject(DatabaseQueryContext context, User user, TableName table, Variable[] columns) throws DatabaseException
      Returns true if the user can insert into a table or view with the given name and given columns, otherwise returns false.
      Throws:
      DatabaseException
    • canUserUpdateTableObject

      public boolean canUserUpdateTableObject(DatabaseQueryContext context, User user, TableName table, Variable[] columns) throws DatabaseException
      Returns true if the user can update a table or view with the given name and given columns, otherwise returns false.
      Throws:
      DatabaseException
    • canUserDeleteFromTableObject

      public boolean canUserDeleteFromTableObject(DatabaseQueryContext context, User user, TableName table) throws DatabaseException
      Returns true if the user can delete from a table or view with the given name and given columns, otherwise returns false.
      Throws:
      DatabaseException
    • canUserCompactTableObject

      public boolean canUserCompactTableObject(DatabaseQueryContext context, User user, TableName table) throws DatabaseException
      Returns true if the user can compact a table with the given name, otherwise returns false.
      Throws:
      DatabaseException
    • canUserCreateProcedureObject

      public boolean canUserCreateProcedureObject(DatabaseQueryContext context, User user, TableName table) throws DatabaseException
      Returns true if the user can create a procedure with the given name, otherwise returns false.
      Throws:
      DatabaseException
    • canUserDropProcedureObject

      public boolean canUserDropProcedureObject(DatabaseQueryContext context, User user, TableName table) throws DatabaseException
      Returns true if the user can drop a procedure with the given name, otherwise returns false.
      Throws:
      DatabaseException
    • canUserCreateSequenceObject

      public boolean canUserCreateSequenceObject(DatabaseQueryContext context, User user, TableName table) throws DatabaseException
      Returns true if the user can create a sequence with the given name, otherwise returns false.
      Throws:
      DatabaseException
    • canUserDropSequenceObject

      public boolean canUserDropSequenceObject(DatabaseQueryContext context, User user, TableName table) throws DatabaseException
      Returns true if the user can drop a sequence with the given name, otherwise returns false.
      Throws:
      DatabaseException
    • setupSystemFunctions

      public void setupSystemFunctions(DatabaseConnection connection, String admin_user) throws DatabaseException
      Sets all the standard functions and procedures available to engine. This creates an entry in the SYS_FUNCTION table for all the dynamic functions and procedures. This may not include the functions exposed though the FunctionFactory interface.
      Throws:
      DatabaseException
    • create

      public void create(String username, String password)
      Creates and sets up a new database to an initial empty state. The creation process involves creating all the system tables and views, adding an administrator user account, creating schema, and setting up the initial grant information for the administrator user.

      The 'username' and 'password' parameter given are set for the administrator account.

    • init

      public void init() throws DatabaseException
      Initializes the database. This opens all the files that are required for the operation of the database. If it finds that the version of the data files are not a compatible version, this method throws an exception.

      NOTE: Perhaps a better name for this method is 'open'.

      Throws:
      DatabaseException
    • shutdown

      public void shutdown() throws DatabaseException
      Cleanly shuts down the database. It is important that this method is called just before the system closes down.

      The main purpose of this method is to ensure any tables that are backed by files and in a 'safe' state and cleanly flushed to the file system.

      If 'delete_on_shutdown' is true, the database will delete itself from the file system when it shuts down.

      Throws:
      DatabaseException
    • exists

      public boolean exists()
      Returns true if the database exists. This must be called before 'init' and 'create'. It checks that the database files exist and we can boot into the database.
    • setDeleteOnShutdown

      public final void setDeleteOnShutdown(boolean status)
      If the 'deleteOnShutdown' flag is set, the database will delete the database from the file system when it is shutdown.

      NOTE: Use with care - if this is set to true and the database is shutdown it will result in total loss of data.

    • isInitialized

      public boolean isInitialized()
      Returns true if the database is initialised.
    • liveCopyTo

      public void liveCopyTo(File path) throws IOException
      Copies all the persistent data in this database (the conglomerate) to the given destination path. This can copy information while the database is 'live'.
      Throws:
      IOException
    • convertToCurrent

      public boolean convertToCurrent(PrintStream out, String admin_username) throws IOException
      Functionality for converting and old database format to the existing format. This would typically be called from a convert tool program.

      Returns true if the convert was successful or false if it wasn't (error message is output to the PrintWriter).

      Throws:
      IOException
    • getDBProcedure

      public DatabaseProcedure getDBProcedure(String procedure_name, DatabaseConnection connection) throws DatabaseException
      Resolves a procedure name into a DBProcedure object. This is used for finding a server side script. It throws a DatabaseException if the procedure could not be resolved or there was an error retrieving it.

      ISSUE: Move this to DatabaseSystem?

      Throws:
      DatabaseException
    • getSystem

      public final DatabaseSystem getSystem()
      Returns the DatabaseSystem that this Database is from.
    • storeSystem

      public final com.mckoi.database.StoreSystem storeSystem()
      Returns the StoreSystem for this Database.
    • stats

      public final Stats stats()
      Convenience static for accessing the global Stats object. Perhaps this should be deprecated?
    • Debug

      public final DebugLogger Debug()
      Returns the DebugLogger implementation from the DatabaseSystem.
    • getTriggerManager

      public final com.mckoi.database.TriggerManager getTriggerManager()
      Returns the system trigger manager.
    • getUserManager

      public final UserManager getUserManager()
      Returns the system user manager.
    • createEvent

      public final Object createEvent(Runnable runner)
      Creates an event for the database dispatcher.
    • postEvent

      public final void postEvent(int time, Object event)
      Posts an event on the database dispatcher.
    • getDataCellCache

      public final com.mckoi.database.DataCellCache getDataCellCache()
      Returns the system DataCellCache.
    • hasShutDown

      public final boolean hasShutDown()
      Returns true if the database has shut down.
    • startShutDownThread

      public final void startShutDownThread()
      Starts the shutdown thread which should contain delegates that shut the database and all its resources down. This method returns immediately.
    • waitUntilShutdown

      public final void waitUntilShutdown()
      Blocks until the database has shut down.
    • execute

      public final void execute(User user, DatabaseConnection database, Runnable runner)
      Executes database functions from the 'run' method of the given runnable instance on the first available worker thread. All database functions must go through a worker thread. If we ensure this, we can easily stop all database functions from executing if need be. Also, we only need to have a certain number of threads active at any one time rather than a unique thread for each connection.
    • registerShutDownDelegate

      public final void registerShutDownDelegate(Runnable delegate)
      Registers the delegate that is executed when the shutdown thread is activated.
    • setIsExecutingCommands

      public final void setIsExecutingCommands(boolean status)
      Controls whether the database is allowed to execute commands or not. If this is set to true, then calls to 'execute' will be executed as soon as there is a free worker thread available. Otherwise no commands are executed until this is enabled.
    • getSingleRowTable

      public final Table getSingleRowTable()
      Returns a static table that has a single row but no columns. This table is useful for certain database operations.
    • finalize

      public void finalize() throws Throwable
      Overrides:
      finalize in class Object
      Throws:
      Throwable