Package com.storedobject.core

Class Database

java.lang.Object

com.storedobject.core.Database

Direct Known Subclasses:

Database

public abstract class Database
extends Object

The abstract database class. In order to write a database driver that works with the stored objects system, one of the tasks is to create a class that implements all the methods of this class. The class should be packaged in a package like "com.storedobject.database.DDD" where DDD is the name of the database driver. For example, the Sybase Adaptive Server Enterprise driver package is "com.storedobject.database.ase" and the Oracle driver package is "com.storedobject.database.oracle".

Author:

Syam

See Also:

• DatabaseDriver
• SQLConnector

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Database()

Method Summary

Modifier and Type	Method	Description
protected abstract boolean	alterPassword(String user, String oldPassword, String newPassword)	Change password of the user on the SQL connection.
abstract String	callProc(String name, String parameter)	Get the SQL statement string to call the stored procedure.
protected final boolean	changePassword(String user, String oldPassword, String newPassword)	Change password of the user on the SQL connection.
List<String[]>	columnDetails(String tableName)
abstract String	columnType(String columnType, int width, int precision)
boolean	createDatabase(String databaseName, String securityPassword)
protected String	createDatabaseDDL(String databaseName)
abstract boolean	createLogin(String user, String password)	Creates a login with the given login name and password.
boolean	createSchema(String schemaName, String securityPassword)
protected abstract String[]	createSchemaDDL(String schemaName)
boolean	createTable(Class<? extends StoredObject> objectClass, String securityPassword)
abstract String	currentTime()	The SQL column that can bring the current time from the database.
String	currentTimeSQL()	The SQL statement that can fetch the current time from the database as first column in its result set.
final boolean	databaseExists(String databaseName)	Check if a database exists or not.
abstract String	databaseSQL(String databaseName)	Part of the SQL string (starting with FROM) that can query details of a database.
List<String[]>	dependentConstraints(String tableName)
boolean	dropDatabase(String databaseName, String securityPassword)
protected abstract String	dropDatabaseDDL(String databaseName)
abstract boolean	dropLogin(String user, String password)	Drops a login with the given login name and password.
static void	ensureMaster()
protected final boolean	executeSQL(String[] sql, String user, String password)	Executes SQL statements.
protected final boolean	executeSQL(String[] sql, String user, String password, boolean ignoreErrors)	Executes SQL statements.
final boolean	executeSQL(String sql, String securityPassword)	Executes a SQL statement as System Admin.
protected final boolean	executeSQL(String sql, String user, String password)	Executes a SQL statements.
protected final boolean	executeSQL(String sql, String user, String password, boolean ignoreErrors)	Executes a SQL statements.
List<String>	foreignKeyConstraintNames(String tableName)
List<String[]>	foreignKeyConstraints(String tableName)
static <D extends Date> String	format(D date)	Format a date value that can be sent to the database as part of a SQL query.
static <D extends Date> String	formatWithTime(D date)	Format a date value with time component that can be sent to the database as part of a SQL query.
static Database	get()	Gets the current database.
Calendar	getCurrentTime()	Current time in the database
abstract String	getObjectClassName()	Get the name of Object class of this database.
abstract String	getSerial(int tag)	Get the SQL statement for generating next Id for the tag passed.
protected RawSQL	getSQL()	A convenient method to create RawSQL object for executing adhoc SQL statements.
String	initialPassword()	The initial password to be used when a user is created for the first time.
abstract boolean	isALogin(RawSQL sql, String user)	Check if the username passed is a valid login of the sql connection passed.
abstract boolean	isALogin(String user, String password)	Checks if the username and password are correct in the current database.
static boolean	isMaster()
static void	lockDatabase()	Locks the database so that login() method can not be invoked again.
static void	login(String driver, String ip, int port, String database, String databaseMaster, String user, String password, String securityLogin)	This method sets up the database.
String	maxTime()	The maximum date-time value allowed in this database as a string.
final Timestamp	maxTimeStamp()	Maximum date-time value converted to Timestamp.
abstract String	modelDatabase()	The name of the model database.
abstract String	name()	The name of the driver.
int	nanoDigits()	Number of nano digits to be used in the format(Timestamp) method.
abstract List<String>	parentTable(String tableName)
protected abstract boolean	resetPassword(String user, String securityPassword, String newPassword)	Reset the password of the user, given the security password.
boolean	schemaExists(String schemaName)
final String	securityLogin()	THe name of the security superuser of the database.
boolean	tableExists(String tableName)
abstract String	userSQL()	The SQL string that can return the login name of the current user as a column value.
boolean	validateSecurityPassword(String password)
boolean	viewExists(String viewName)

Methods inherited from class java.lang.Object

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

Constructor Details

Database

protected Database()

Method Details

login

public static void login(String driver,
 String ip,
 int port,
 String database,
 String databaseMaster,
 String user,
 String password,
 String securityLogin)
                  throws Exception

This method sets up the database.

Parameters:

driver - Name of the database driver

ip - The IP address in dotted decimal form or the DNS entry of the server on which database is running.

port - The TCP port number on which the database is listening.

database - Name of the database to connect to.

databaseMaster - Name of the master database to connect to.

user - The login name of the user. If a database name to be specified, pass it along with the login name separated by a slash ("/") character. For example: "john/inventory".

password - The password of the user.

securityLogin - Security login (For example, for PostgreSQL, the default is "postgres").

Throws:

Exception - Any

get

public static Database get()

Gets the current database.

Returns:

Returns the current database.

lockDatabase

public static void lockDatabase()

Locks the database so that login() method can not be invoked again.

name

public abstract String name()

The name of the driver. For example, Sybase Adaptive Server Enterprise driver name is "ASE".

Returns:

The database driver name

securityLogin

public final String securityLogin()

THe name of the security superuser of the database. For example, in the case of Sybase Adaptive Server Enterprise, it will return "sa".

Returns:

The login name of the security superuser.

modelDatabase

public abstract String modelDatabase()

The name of the model database. Such a concept is there in some database systems.

Returns:

The name of the model database. Null string may be returned if such a concept does not exist.

userSQL

public abstract String userSQL()

The SQL string that can return the login name of the current user as a column value.

Returns:

SQL that can be executed to get the name of the current user.

databaseSQL

public abstract String databaseSQL(String databaseName)

Part of the SQL string (starting with FROM) that can query details of a database.

Parameters:

databaseName - Database name.

Returns:

Part of the SQL string.

isALogin

public abstract boolean isALogin(RawSQL sql,
 String user)

Check if the username passed is a valid login of the sql connection passed.

Parameters:

sql - The sql connection on which the user needs to be verified.

user - The login name.

Returns:

True if the use is a valid login.

isALogin

public abstract boolean isALogin(String user,
 String password)

Checks if the username and password are correct in the current database.

Parameters:

user - The name of the login to check.

password - The password.

Returns:

True if the login is correct.

initialPassword

public String initialPassword()

The initial password to be used when a user is created for the first time. The default value is "welcome" without quotes.

Returns:

The initial password.

createLogin

public abstract boolean createLogin(String user,
 String password)

Creates a login with the given login name and password.

Parameters:

user - The login name.

password - The security password.

Returns:

True if successfully created.

dropLogin

public abstract boolean dropLogin(String user,
 String password)

Drops a login with the given login name and password.

Parameters:

user - The login name.

password - The security password.

Returns:

True if successfully dropped.

changePassword

protected final boolean changePassword(String user,
 String oldPassword,
 String newPassword)

Change password of the user on the SQL connection. This will reset the SQLConnector's password setting if the user is currently connected.

Parameters:

user - The login name whose password needs to be changed.

oldPassword - Old password.

newPassword - New password.

Returns:

True if the password is successfully changed.

alterPassword

protected abstract boolean alterPassword(String user,
 String oldPassword,
 String newPassword)

Change password of the user on the SQL connection.

Parameters:

user - The login name whose password needs to be changed.

oldPassword - Old password.

newPassword - New password.

Returns:

True if the password is successfully changed.

resetPassword

protected abstract boolean resetPassword(String user,
 String securityPassword,
 String newPassword)

Reset the password of the user, given the security password.

Parameters:

user - The login name whose password needs to be changed.

securityPassword - The security superuser's password

newPassword - The password for the user.

Returns:

True if the password is successfully changed.

maxTime

public String maxTime()

The maximum date-time value allowed in this database as a string. For example, on the Sybase Adaptive Server Enterprise, the value returned will be "7910-12-31 23:59:59". Generally, it will be returned as 1 second less than the maximum allowed value in the database. The default implementation returns "7910-12-31 23:59:59" and it may be good enough for other database systems. But, it needs to be changed if the database system supports only values less than this.

Returns:

The maximum date-time value allowed.

currentTime

public abstract String currentTime()

The SQL column that can bring the current time from the database. For example, in the case of Sybase Adaptive Server Enterprise, it will return "getdate()".

Returns:

The SQL column that can bring the current time from the database.

getCurrentTime

public Calendar getCurrentTime()

Current time in the database

Returns:

Current time

currentTimeSQL

public String currentTimeSQL()

The SQL statement that can fetch the current time from the database as first column in its result set. The default implementation returns "SELECT X" where X is the value returned by the currentTime() method.

Returns:

The SQL statement.

callProc

public abstract String callProc(String name,
 String parameter)

Get the SQL statement string to call the stored procedure. For example, in the case of Sybase Adaptive Server Enterprise, if a procedure called "AuthorizeTran" needs to be invoked with parameters "25, 345, 23", this method will return "EXEC AuthorizeTran 25, 345, 23".

Parameters:

name - The name of the stored procedure.

parameter - Parameter to the stored procedure.

Returns:

The SQL statement to execute for invoking the stored procedure.

getSerial

public abstract String getSerial(int tag)

Get the SQL statement for generating next Id for the tag passed.

Parameters:

tag - Tag for which statement is needed.

Returns:

Serial SQL for the tag

getObjectClassName

public abstract String getObjectClassName()

Get the name of Object class of this database.

Returns:

Full name of the class

format

public static <D extends Date> String format(D date)

Format a date value that can be sent to the database as part of a SQL query.

Type Parameters:

D - Date type

Parameters:

date - Date to be formatted

Returns:

Formatted date.

formatWithTime

public static <D extends Date> String formatWithTime(D date)

Format a date value with time component that can be sent to the database as part of a SQL query. It should return typically in a format similar to "yyyy-MM-dd HH:mm:ss.ssssss". Please note the nanos. Some databases may not support so many digits in the nanos and in such cases, only up to the number of digits supported should be returned. The default implementation returns the number of digits returned by the method nanoDigits(). So, if you just want to adjust the number of nano digits returned, override the nanoDigits() method.

Type Parameters:

D - Date type

Parameters:

date - Date to be formatted

Returns:

Formatted date.

nanoDigits

public int nanoDigits()

Number of nano digits to be used in the format(Timestamp) method. The default implementation returns 6.

Returns:

Number of nano digits.

executeSQL

public final boolean executeSQL(String sql,
 String securityPassword)

Executes a SQL statement as System Admin.

Parameters:

sql - SQL statement to be executed.

securityPassword - Password of System Admin

Returns:

True/False

executeSQL

protected final boolean executeSQL(String sql,
 String user,
 String password)

Executes a SQL statements.

Parameters:

sql - SQL statement to be executed.

user - User name.

password - Password

Returns:

True/False

executeSQL

protected final boolean executeSQL(String sql,
 String user,
 String password,
 boolean ignoreErrors)

Executes a SQL statements.

Parameters:

sql - SQL statement to be executed.

user - User name.

password - Password

ignoreErrors - Ignore errors

Returns:

True/False

executeSQL

protected final boolean executeSQL(String[] sql,
 String user,
 String password)

Executes SQL statements.

Parameters:

sql - SQL statement to be executed.

user - User name.

password - Password

Returns:

True/False

executeSQL

protected final boolean executeSQL(String[] sql,
 String user,
 String password,
 boolean ignoreErrors)

Executes SQL statements.

Parameters:

sql - SQL statement to be executed.

user - User name.

password - Password

ignoreErrors - Ignore errors

Returns:

True/False

maxTimeStamp

public final Timestamp maxTimeStamp()

Maximum date-time value converted to Timestamp.

Returns:

The maximum date-time value defined by maxTime() method converted to Timestamp.

getSQL

protected RawSQL getSQL()

A convenient method to create RawSQL object for executing adhoc SQL statements.

Returns:

A properly constructed RawSQL object.

schemaExists

public boolean schemaExists(String schemaName)

databaseExists

public final boolean databaseExists(String databaseName)

Check if a database exists or not.

Parameters:

databaseName - Database name.

Returns:

True/false.

tableExists

public boolean tableExists(String tableName)

viewExists

public boolean viewExists(String viewName)

foreignKeyConstraintNames

public List<String> foreignKeyConstraintNames(String tableName)

foreignKeyConstraints

public List<String[]> foreignKeyConstraints(String tableName)

dependentConstraints

public List<String[]> dependentConstraints(String tableName)

parentTable

public abstract List<String> parentTable(String tableName)

columnType

public abstract String columnType(String columnType,
 int width,
 int precision)

columnDetails

public List<String[]> columnDetails(String tableName)

dropDatabaseDDL

protected abstract String dropDatabaseDDL(String databaseName)

dropDatabase

public boolean dropDatabase(String databaseName,
 String securityPassword)

createDatabaseDDL

protected String createDatabaseDDL(String databaseName)

createDatabase

public boolean createDatabase(String databaseName,
 String securityPassword)

createSchemaDDL

protected abstract String[] createSchemaDDL(String schemaName)

createSchema

public boolean createSchema(String schemaName,
 String securityPassword)

createTable

public boolean createTable(Class<? extends StoredObject> objectClass,
 String securityPassword)
                    throws Exception

Throws:

Exception

validateSecurityPassword

public boolean validateSecurityPassword(String password)
                                 throws Exception

Throws:

Exception

isMaster

public static boolean isMaster()

ensureMaster

public static void ensureMaster()
                         throws SOException

Throws:

SOException