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java.lang.Objectorg.apache.empire.db.DBObject
org.apache.empire.db.DBExpr
org.apache.empire.db.DBColumnExpr
org.apache.empire.db.expr.column.DBCountExpr
public class DBCountExpr
This class is used to add the "count" statement to the SQL-Command.
There is no need to explicitly create instances of this class.
Instead use or @link DBColumnExpr#count()
Field Summary |
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Fields inherited from class org.apache.empire.db.DBColumnExpr |
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attributes, beanPropertyName, DBCOLATTR_TITLE, DBCOLATTR_TYPE, options |
Fields inherited from class org.apache.empire.db.DBExpr |
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CTX_ALIAS, CTX_ALL, CTX_DEFAULT, CTX_FULLNAME, CTX_NAME, CTX_NOPARENTHESES, CTX_VALUE |
Constructor Summary | |
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DBCountExpr(DBColumnExpr expr,
boolean distinct)
Constructs a DBCountExpr. |
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DBCountExpr(DBRowSet rowset)
Constructs a DBCountExpr. |
Method Summary | |
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void |
addReferencedColumns(Set<DBColumn> list)
Internal function to obtain all DBColumnExpr-objects used by this expression. |
void |
addSQL(StringBuilder sql,
long context)
Creates the SQL-Command adds the String "count(*)" to the SQL-Command. |
Element |
addXml(Element parent,
long flags)
this adds the column description to the parent element |
DBDatabase |
getDatabase()
Returns the current DBDatabase object. |
DataType |
getDataType()
Returns the data type: DT_INTEGER. |
String |
getName()
Returns the String "count". |
DBColumn |
getUpdateColumn()
Returns null. |
boolean |
isAggregate()
Returns true since the count function is an aggregate function. |
Methods inherited from class org.apache.empire.db.DBColumnExpr |
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abs, append, as, as, asc, avg, cmp, coalesce, convertTo, convertTo, count, countDistinct, day, decode, decode, decode, decode, decode, decode, desc, detectDataType, divideBy, getAttribute, getBeanPropertyName, getControlType, getExprFromPhrase, getExprFromPhrase, getOptions, getSourceColumn, getTitle, in, indexOf, indexOf, indexOf, is, isBetween, isGreaterThan, isLessOrEqual, isMoreOrEqual, isNot, isNotBetween, isSmallerThan, length, like, like, likeLower, likeUpper, lower, max, min, minus, minus, month, multiplyWith, notIn, notLike, nvl, parenthesis, plus, plus, replace, reverse, round, setAttribute, setBeanPropertyName, setControlType, setOptions, setTitle, substring, substring, substring, substring, substring, substring, sum, toChar, toChar, trim, trimLeft, trimRight, trunc, upper, when, year |
Methods inherited from class org.apache.empire.db.DBExpr |
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getObjectValue, getValueClass |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public DBCountExpr(DBRowSet rowset)
rowset
- the rowsetpublic DBCountExpr(DBColumnExpr expr, boolean distinct)
expr
- the columndistinct
- set true for distinct countMethod Detail |
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public DBDatabase getDatabase()
getDatabase
in class DBObject
public DataType getDataType()
getDataType
in interface ColumnExpr
getDataType
in class DBColumnExpr
DataType
public String getName()
getName
in interface ColumnExpr
getName
in class DBColumnExpr
public DBColumn getUpdateColumn()
getUpdateColumn
in class DBColumnExpr
public boolean isAggregate()
isAggregate
in class DBColumnExpr
public void addReferencedColumns(Set<DBColumn> list)
DBExpr
addReferencedColumns
in class DBExpr
list
- list to which all used column expressions must be addedDBExpr.addReferencedColumns(Set)
public void addSQL(StringBuilder sql, long context)
addSQL
in class DBExpr
sql
- the SQL-Commandcontext
- the current SQL-Command contextpublic Element addXml(Element parent, long flags)
addXml
in class DBColumnExpr
parent
- the parent element to which to append the column descriptionflags
- currently not used
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