edu.ucsb.nceas.dbadapter

Class AbstractDatabase

java.lang.Object

edu.ucsb.nceas.dbadapter.AbstractDatabase

Direct Known Subclasses:

OracleAdapter, PostgresqlAdapter, SqlserverAdapter

public abstract class AbstractDatabase
extends java.lang.Object

Java offers uniform database access through the use of JDBC. But many databases still use different SQL implementations and conventions. Thus this class offers extended programming interface that all subclasses should implement to gain access to different databases. To add a new database adapter class you must create a new class Adapter that extends edu.ucsb.nceas.dbadapter.AbstarctDatabase (where dbname is the name of the database or database driver you wish to add to your application). AbstarctDatabase is an abstract class, thus the subclasses need to implement the abstract methods.

Constructor Summary

Constructors

Constructor and Description
AbstractDatabase()

Method Summary

Modifier and Type	Method and Description
static java.lang.Object	createObject(java.lang.String className) Instantiate a class using the name of the class at runtime
abstract java.lang.String	getDateTimeFunction() The function name that gets the current date and time from the database server
abstract java.lang.String	getIsNULLFunction() The function name that is used to return non-NULL value
abstract java.lang.String	getLeftJoinQuery(java.lang.String selectFields, java.lang.String tableA, java.lang.String tableB, java.lang.String joinCriteria, java.lang.String nonJoinCriteria) Syntax for doing a left join Add 'a.' in front of the fields for first table and 'b.' in front of the fields for the second table
abstract java.lang.String	getPagedQuery(java.lang.String queryWithOrderBy, java.lang.Integer start, java.lang.Integer count) for generating a query for paging
abstract java.lang.String	getReplicationDocumentListSQL() This method will return the sql command to get document list in xml_document in replication.
abstract java.lang.String	getStringDelimiter() The character that the specific database implementation uses to indicate string literals in SQL.
abstract long	getUniqueID(java.sql.Connection conn, java.lang.String tableName) Unique ID generator
static void	main(java.lang.String[] args) the main routine used to test the dbadapter utility.
java.lang.String	toDate(java.lang.String dateString, java.lang.String format) MSSQL didn't support to_date function which to transfer a text string to date type.

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractDatabase

public AbstractDatabase()

Method Detail

getUniqueID

public abstract long getUniqueID(java.sql.Connection conn,
                                 java.lang.String tableName)
                          throws java.sql.SQLException

Unique ID generator

Parameters:

conn - db connection in which the unique id was generated

tableName - the table which unique id was generate

Returns:

return the generated unique id as a long type

Throws:

java.sql.SQLException -
any SQLException that can be thrown during the db operation

getDateTimeFunction

public abstract java.lang.String getDateTimeFunction()

The function name that gets the current date and time from the database server

Returns:

return the current date and time function name

getIsNULLFunction

public abstract java.lang.String getIsNULLFunction()

The function name that is used to return non-NULL value

Returns:

return the non-NULL function name

getStringDelimiter

public abstract java.lang.String getStringDelimiter()

The character that the specific database implementation uses to indicate string literals in SQL. This will usually be a single qoute (').

Returns:

return the string delimiter

toDate

public java.lang.String toDate(java.lang.String dateString,
                               java.lang.String format)

MSSQL didn't support to_date function which to transfer a text string to date type. But Oracle and Postsql do.

getLeftJoinQuery

public abstract java.lang.String getLeftJoinQuery(java.lang.String selectFields,
                                                  java.lang.String tableA,
                                                  java.lang.String tableB,
                                                  java.lang.String joinCriteria,
                                                  java.lang.String nonJoinCriteria)

Syntax for doing a left join Add 'a.' in front of the fields for first table and 'b.' in front of the fields for the second table

Parameters:

selectFields - fields that you want to be selected

tableA - first table in the join

tableB - second table in the join

joinCriteria - the criteria based on which the join will be made

nonJoinCriteria - all other criterias

Returns:

return the string for teh select query

createObject

public static java.lang.Object createObject(java.lang.String className)
                                     throws java.lang.Exception

Instantiate a class using the name of the class at runtime

Parameters:

className - the fully qualified name of the class to instantiate

Throws:

java.lang.Exception

main

public static void main(java.lang.String[] args)

the main routine used to test the dbadapter utility.

getReplicationDocumentListSQL

public abstract java.lang.String getReplicationDocumentListSQL()

This method will return the sql command to get document list in xml_document in replication. Because it involes outer join, so this method is very flexible.

Returns:

getPagedQuery

public abstract java.lang.String getPagedQuery(java.lang.String queryWithOrderBy,
                                               java.lang.Integer start,
                                               java.lang.Integer count)

for generating a query for paging

Parameters:

queryWithOrderBy - - the complete query with SELECT, FROM, WHERE and ORDER BY clauses

start - the row number to start from

count - the number of records from start to return

Returns:

query specific to the RDBMS in use