org.prorefactor.core.schema
Class Schema

java.lang.Object
  org.prorefactor.core.schema.Schema

public class Schema
extends java.lang.Object

Schema is a singleton with methods and fields for working with database schema names, and references to those from 4gl compile units.

Field Summary

static Database	nullDatabase
static Table	nullTable

Method Summary

java.lang.String	aliasCreate(java.lang.String aliasname, java.lang.String dbname) Add a database alias.
void	aliasDelete(java.lang.String aliasname) Delete a database alias.
void	clear()
java.util.Iterator	getAllTablesIterator() Get an iterator through all tables, sorted by db.table name.
java.util.TreeSet<Database>	getDbSet() Get databases sorted by name.
static Schema	getInstance() Schema is a "Singleton"
void	loadSchema(java.lang.String from) Load schema names and RECID from a flat file.
Database	lookupDatabase(java.lang.String inName) Lookup Database, with alias checks.
Field	lookupField(java.lang.String dbName, java.lang.String tableName, java.lang.String fieldName) Lookup a Field, given the db, table, and field names
Table	lookupTable(java.lang.String inName) Lookup a table by name.
Table	lookupTable(java.lang.String dbName, java.lang.String tableName) Lookup a table, given a database name and a table name.
Field	lookupUnqualifiedField(java.lang.String name) Lookup an unqualified schema field name.

Methods inherited from class java.lang.Object

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

Field Detail

nullDatabase

public static Database nullDatabase

nullTable

public static Table nullTable

Method Detail

getDbSet

public java.util.TreeSet<Database> getDbSet()

Get databases sorted by name.

getInstance

public static Schema getInstance()

Schema is a "Singleton"

clear

public void clear()

aliasCreate

public java.lang.String aliasCreate(java.lang.String aliasname,
                                    java.lang.String dbname)

Add a database alias.

Parameters:

aliasname - The name for the alias

dbname - The database's logical name

Returns:

Empty string.

aliasDelete

public void aliasDelete(java.lang.String aliasname)

Delete a database alias.

Parameters:

aliasname - The name for the alias, null or empty string to delete all.

getAllTablesIterator

public java.util.Iterator getAllTablesIterator()

Get an iterator through all tables, sorted by db.table name.

loadSchema

public void loadSchema(java.lang.String from)
                throws java.io.IOException

Load schema names and RECID from a flat file.

Parameters:

from - The filename to read from.

Throws:

java.io.IOException

lookupDatabase

public Database lookupDatabase(java.lang.String inName)

Lookup Database, with alias checks.

lookupField

public Field lookupField(java.lang.String dbName,
                         java.lang.String tableName,
                         java.lang.String fieldName)

Lookup a Field, given the db, table, and field names

lookupTable

public Table lookupTable(java.lang.String inName)

Lookup a table by name.

Parameters:

inName - The string table name to lookup.

Returns:

A Table, or null if not found. If a name like "db.table" fails on the first lookup try, we next search dictdb for the table, in case it's something like "sports._file". In that case, the Table from the "dictdb" database would be returned. We don't keep meta-schema records in the rest of the databases.

lookupTable

public Table lookupTable(java.lang.String dbName,
                         java.lang.String tableName)

Lookup a table, given a database name and a table name.

lookupUnqualifiedField

public Field lookupUnqualifiedField(java.lang.String name)

Lookup an unqualified schema field name. Does not test for uniqueness. That job is left to the compiler. (In fact, anywhere this is run, the compiler would check that the field name is also unique against temp/work tables.) Returns null if nothing found.