Package adql.db
Class DBCommonColumn
- java.lang.Object
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- adql.db.DBCommonColumn
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- All Implemented Interfaces:
DBColumn
public class DBCommonColumn extends java.lang.Object implements DBColumn
This is a special column which exists only after a NATURAL JOIN or a JOIN ... USING between two tables. It lets unify several columns of the joined tables in a single column. Thus, the writer of an ADQL query can use the column name without table prefix (since after the join there will be only one) or with a prefix table of the joined tables. The list of all covered tables is stored in this object and can be extended in case of several JOINs.- Since:
- 1.2
- Version:
- 1.3 (05/2015)
- Author:
- Grégory Mantelet (ARI) - gmantele@ari.uni-heidelberg.de
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Field Summary
Fields Modifier and Type Field Description protected DBColumn
generalColumnDesc
protected java.util.ArrayList<DBTable>
lstCoveredTables
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Constructor Summary
Constructors Constructor Description DBCommonColumn(DBColumn leftCol, DBColumn rightCol)
Create a column which merges both of the given columns.DBCommonColumn(DBCommonColumn toCopy, java.lang.String dbName, java.lang.String adqlName)
Constructor by copy.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description protected void
addCoveredTable(DBTable table)
Add a table that this common column must cover from now.DBColumn
copy(java.lang.String dbName, java.lang.String adqlName, DBTable dbTable)
WARNING: This copy function does not make a real copy of this DBCommonColumn ! It returns a modified copy of the general column description it contains.java.lang.String
getADQLName()
Gets the name of this column (without any prefix and double-quotes).java.util.Iterator<DBTable>
getCoveredTables()
Get an iterator over the list of all tables covered by this common column.DBType
getDatatype()
Get the type of this column (as closed as possible from the "database" type).java.lang.String
getDBName()
Gets the name of this column in the "database".DBTable
getTable()
Gets the table which contains thisDBColumn
.
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Constructor Detail
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DBCommonColumn
public DBCommonColumn(DBColumn leftCol, DBColumn rightCol) throws UnresolvedJoinException
Create a column which merges both of the given columns. This specialDBColumn
implementation is not associated with one table, and can be listed in aDBTable
ONLY IF the latter is the result of a sub-query (seeADQLQuery.getResultingColumns()
). A column resulting from a tables join is common only to the joined tables. That's why a list of all tables covered by this column is created or update at each merge. It can be accessed thanks togetCoveredTables()
. Note: In the case one or both of the columns to join areDBCommonColumn
, the list of their covered tables are also merged.- Parameters:
leftCol
- Column of the left join table. May be aDBCommonColumn
.rightCol
- Column of the right join table. May be aDBCommonColumn
.- Throws:
UnresolvedJoinException
- If the type of the two given columns are not roughly (just testing numeric, string or geometry) compatible.
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DBCommonColumn
public DBCommonColumn(DBCommonColumn toCopy, java.lang.String dbName, java.lang.String adqlName)
Constructor by copy. It returns a copy of this instance ofDBCommonColumn
. Note: The list of covered tables is NOT deeply copied!- Parameters:
toCopy
- TheDBCommonColumn
to copy.dbName
- The new DB name of thisDBCommonColumn
.adqlName
- The new ADQL name of thisDBCommonColumn
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Method Detail
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getADQLName
public final java.lang.String getADQLName()
Description copied from interface:DBColumn
Gets the name of this column (without any prefix and double-quotes).- Specified by:
getADQLName
in interfaceDBColumn
- Returns:
- Its ADQL name.
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getDBName
public final java.lang.String getDBName()
Description copied from interface:DBColumn
Gets the name of this column in the "database".
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getDatatype
public final DBType getDatatype()
Description copied from interface:DBColumn
Get the type of this column (as closed as possible from the "database" type).
Note: The returned type should be as closed as possible from a type listed by the IVOA in the TAP protocol description into the section UPLOAD.
- Specified by:
getDatatype
in interfaceDBColumn
- Returns:
- Its type.
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getTable
public final DBTable getTable()
Description copied from interface:DBColumn
Gets the table which contains thisDBColumn
.
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getCoveredTables
public final java.util.Iterator<DBTable> getCoveredTables()
Get an iterator over the list of all tables covered by this common column.- Returns:
- Iterator over all covered tables.
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addCoveredTable
protected void addCoveredTable(DBTable table)
Add a table that this common column must cover from now. Warning: no unicity check is never done !- Parameters:
table
- Table to add in the covered tables list.
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copy
public DBColumn copy(java.lang.String dbName, java.lang.String adqlName, DBTable dbTable)
WARNING: This copy function does not make a real copy of this DBCommonColumn ! It returns a modified copy of the general column description it contains. Note: To make a real copy of this DBCommonColumn use the Constructor by copyDBCommonColumn(DBCommonColumn, String, String)
.- Specified by:
copy
in interfaceDBColumn
- Parameters:
dbName
- Its new DB name.adqlName
- Its new ADQL name.dbTable
- Its new DBTable- Returns:
- A modified copy of the general column description this common column represents.
- See Also:
DBColumn.copy(java.lang.String, java.lang.String, adql.db.DBTable)
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