org.h2.table

Class Column

java.lang.Object

org.h2.table.Column

All Implemented Interfaces:

ColumnTemplate, HasSQL, Typed

public final class Column
extends java.lang.Object
implements HasSQL, Typed, ColumnTemplate

This class represents a column in a table.

Field Summary

Fields

Modifier and Type	Field and Description
static int	NOT_NULLABLE This column is not nullable.
static int	NULLABLE This column is nullable.
static int	NULLABLE_UNKNOWN It is not know whether this column is nullable.
static java.lang.String	ROWID The name of the rowid pseudo column.

Fields inherited from interface org.h2.util.HasSQL

ADD_PLAN_INFORMATION, DEFAULT_SQL_FLAGS, NO_CASTS, QUOTE_ONLY_WHEN_REQUIRED, REPLACE_LOBS_FOR_TRACE, TRACE_SQL_FLAGS

Constructor Summary

Constructors

Constructor and Description
Column(java.lang.String name, TypeInfo type)
Column(java.lang.String name, TypeInfo type, Table table, int columnId)

Method Summary

Modifier and Type	Method and Description
Value	convert(CastDataProvider provider, Value v) Convert a value to this column's type without precision and scale checks.
void	copy(Column source) Copy the data of the source column into the current column.
boolean	equals(java.lang.Object o)
Column	getClone()
int	getColumnId()
java.lang.String	getComment()
java.lang.String	getCreateSQL()
java.lang.String	getCreateSQL(boolean forMeta) Get this columns part of CREATE TABLE SQL statement.
java.lang.String	getCreateSQLWithoutName()
Expression	getDefaultExpression()
java.lang.String	getDefaultSQL()
Domain	getDomain()
Expression	getEffectiveDefaultExpression()
Expression	getEffectiveOnUpdateExpression()
SequenceOptions	getIdentityOptions() Returns identity column options, or null if sequence was already created or this column is not an identity column.
java.lang.String	getName()
Expression	getOnUpdateExpression()
java.lang.String	getOnUpdateSQL()
int	getSelectivity() Get the selectivity of the column.
Sequence	getSequence()
java.lang.String	getSQL(int sqlFlags) Get the SQL statement of this expression.
java.lang.StringBuilder	getSQL(java.lang.StringBuilder builder, int sqlFlags) Appends the SQL statement of this object to the specified builder.
java.lang.StringBuilder	getSQLWithTable(java.lang.StringBuilder builder, int sqlFlags) Appends the table name and column name to the specified builder.
Table	getTable()
TypeInfo	getType() Returns the data type.
boolean	getVisible()
int	hashCode()
boolean	hasIdentityOptions() Whether the column has any identity options.
void	initializeSequence(SessionLocal session, Schema schema, int id, boolean temporary) Initialize the sequence for this column.
boolean	isDefaultOnNull()
boolean	isGenerated() Returns whether this column is a generated column.
boolean	isGeneratedAlways() Returns whether this column is a generated column or always generated identity column.
boolean	isIdentity() Returns whether this column is an identity column.
boolean	isNullable()
boolean	isPrimaryKey()
boolean	isRowId() Returns whether this column is a row identity column.
boolean	isWideningConversion(Column newColumn) Check whether the new column is of the same type and not more restricted than this column.
void	prepareExpressions(SessionLocal session) Prepare all expressions of this column or domain.
void	rename(java.lang.String newName) Rename the column.
void	setComment(java.lang.String comment)
void	setDefaultExpression(SessionLocal session, Expression defaultExpression) Set the default expression.
void	setDefaultOnNull(boolean defaultOnNull)
void	setDomain(Domain domain)
void	setGeneratedExpression(Expression expression) Set the default value in the form of a generated expression of other columns.
void	setIdentityOptions(SequenceOptions identityOptions, boolean generatedAlways) Set the identity options of this column.
void	setNullable(boolean b)
void	setOnUpdateExpression(SessionLocal session, Expression onUpdateExpression) Set the on update expression.
void	setPrimaryKey(boolean primaryKey)
void	setRowId(boolean rowId) Set row identity flag.
void	setSelectivity(int selectivity) Set the new selectivity of a column.
void	setSequence(Sequence sequence, boolean generatedAlways) Set the sequence to generate the value.
void	setTable(Table table, int columnId) Set the table and column id.
void	setVisible(boolean b)
java.lang.String	toString()
static java.lang.StringBuilder	writeColumns(java.lang.StringBuilder builder, Column[] columns, int sqlFlags) Appends the specified columns to the specified builder.
static java.lang.StringBuilder	writeColumns(java.lang.StringBuilder builder, Column[] columns, java.lang.String separator, java.lang.String suffix, int sqlFlags) Appends the specified columns to the specified builder.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.h2.util.HasSQL

getTraceSQL

Field Detail

ROWID

public static final java.lang.String ROWID

The name of the rowid pseudo column.

See Also:

Constant Field Values

NOT_NULLABLE

public static final int NOT_NULLABLE

This column is not nullable.

See Also:

Constant Field Values

NULLABLE

public static final int NULLABLE

This column is nullable.

See Also:

Constant Field Values

NULLABLE_UNKNOWN

public static final int NULLABLE_UNKNOWN

It is not know whether this column is nullable.

See Also:

Constant Field Values

Constructor Detail

Column

public Column(java.lang.String name,
              TypeInfo type)

Column

public Column(java.lang.String name,
              TypeInfo type,
              Table table,
              int columnId)

Method Detail

writeColumns

public static java.lang.StringBuilder writeColumns(java.lang.StringBuilder builder,
                                                   Column[] columns,
                                                   int sqlFlags)

Appends the specified columns to the specified builder.

Parameters:

builder - string builder

columns - columns

sqlFlags - formatting flags

Returns:

the specified string builder

writeColumns

public static java.lang.StringBuilder writeColumns(java.lang.StringBuilder builder,
                                                   Column[] columns,
                                                   java.lang.String separator,
                                                   java.lang.String suffix,
                                                   int sqlFlags)

Appends the specified columns to the specified builder.

Parameters:

builder - string builder

columns - columns

separator - separator

suffix - additional SQL to append after each column

sqlFlags - formatting flags

Returns:

the specified string builder

equals

public boolean equals(java.lang.Object o)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

getClone

public Column getClone()

convert

public Value convert(CastDataProvider provider,
                     Value v)

Convert a value to this column's type without precision and scale checks.

Parameters:

provider - the cast information provider

v - the value

Returns:

the value

isIdentity

public boolean isIdentity()

Returns whether this column is an identity column.

Returns:

whether this column is an identity column

isGenerated

public boolean isGenerated()

Returns whether this column is a generated column.

Returns:

whether this column is a generated column

isGeneratedAlways

public boolean isGeneratedAlways()

Returns whether this column is a generated column or always generated identity column.

Returns:

whether this column is a generated column or always generated identity column

setGeneratedExpression

public void setGeneratedExpression(Expression expression)

Set the default value in the form of a generated expression of other columns.

Parameters:

expression - the computed expression

setTable

public void setTable(Table table,
                     int columnId)

Set the table and column id.

Parameters:

table - the table

columnId - the column index

getTable

public Table getTable()

setDefaultExpression

public void setDefaultExpression(SessionLocal session,
                                 Expression defaultExpression)

Description copied from interface: ColumnTemplate

Set the default expression.

Specified by:

setDefaultExpression in interface ColumnTemplate

Parameters:

session - the session

defaultExpression - the default expression

setOnUpdateExpression

public void setOnUpdateExpression(SessionLocal session,
                                  Expression onUpdateExpression)

Description copied from interface: ColumnTemplate

Set the on update expression.

Specified by:

setOnUpdateExpression in interface ColumnTemplate

Parameters:

session - the session

onUpdateExpression - the on update expression

getColumnId

public int getColumnId()

getSQL

public java.lang.String getSQL(int sqlFlags)

Description copied from interface: HasSQL

Get the SQL statement of this expression. This may not always be the original SQL statement, specially after optimization.

Specified by:

getSQL in interface HasSQL

Parameters:

sqlFlags - formatting flags

Returns:

the SQL statement

getSQL

public java.lang.StringBuilder getSQL(java.lang.StringBuilder builder,
                                      int sqlFlags)

Description copied from interface: HasSQL

Appends the SQL statement of this object to the specified builder.

Specified by:

getSQL in interface HasSQL

Parameters:

builder - string builder

sqlFlags - formatting flags

Returns:

the specified string builder

getSQLWithTable

public java.lang.StringBuilder getSQLWithTable(java.lang.StringBuilder builder,
                                               int sqlFlags)

Appends the table name and column name to the specified builder.

Parameters:

builder - the string builder

sqlFlags - formatting flags

Returns:

the specified string builder

getName

public java.lang.String getName()

getType

public TypeInfo getType()

Description copied from interface: Typed

Returns the data type.

Specified by:

getType in interface Typed

Returns:

the data type

setNullable

public void setNullable(boolean b)

getVisible

public boolean getVisible()

setVisible

public void setVisible(boolean b)

getDomain

public Domain getDomain()

Specified by:

getDomain in interface ColumnTemplate

setDomain

public void setDomain(Domain domain)

Specified by:

setDomain in interface ColumnTemplate

isRowId

public boolean isRowId()

Returns whether this column is a row identity column.

Returns:

true for _ROWID_ column, false otherwise

setRowId

public void setRowId(boolean rowId)

Set row identity flag.

Parameters:

rowId - true _ROWID_ column, false otherwise

initializeSequence

public void initializeSequence(SessionLocal session,
                               Schema schema,
                               int id,
                               boolean temporary)

Initialize the sequence for this column.

Parameters:

session - the session

schema - the schema where the sequence should be generated

id - the object id

temporary - true if the sequence is temporary and does not need to be stored

prepareExpressions

public void prepareExpressions(SessionLocal session)

Description copied from interface: ColumnTemplate

Prepare all expressions of this column or domain.

Specified by:

prepareExpressions in interface ColumnTemplate

Parameters:

session - the session

getCreateSQLWithoutName

public java.lang.String getCreateSQLWithoutName()

getCreateSQL

public java.lang.String getCreateSQL()

getCreateSQL

public java.lang.String getCreateSQL(boolean forMeta)

Get this columns part of CREATE TABLE SQL statement.

Parameters:

forMeta - whether this is for the metadata table

Returns:

the SQL statement

isNullable

public boolean isNullable()

getDefaultExpression

public Expression getDefaultExpression()

Specified by:

getDefaultExpression in interface ColumnTemplate

getEffectiveDefaultExpression

public Expression getEffectiveDefaultExpression()

Specified by:

getEffectiveDefaultExpression in interface ColumnTemplate

getOnUpdateExpression

public Expression getOnUpdateExpression()

Specified by:

getOnUpdateExpression in interface ColumnTemplate

getEffectiveOnUpdateExpression

public Expression getEffectiveOnUpdateExpression()

Specified by:

getEffectiveOnUpdateExpression in interface ColumnTemplate

hasIdentityOptions

public boolean hasIdentityOptions()

Whether the column has any identity options.

Returns:

true if yes

setIdentityOptions

public void setIdentityOptions(SequenceOptions identityOptions,
                               boolean generatedAlways)

Set the identity options of this column.

Parameters:

identityOptions - identity column options

generatedAlways - whether value should be always generated

getIdentityOptions

public SequenceOptions getIdentityOptions()

Returns identity column options, or null if sequence was already created or this column is not an identity column.

Returns:

identity column options, or null

setDefaultOnNull

public void setDefaultOnNull(boolean defaultOnNull)

isDefaultOnNull

public boolean isDefaultOnNull()

rename

public void rename(java.lang.String newName)

Rename the column. This method will only set the column name to the new value.

Parameters:

newName - the new column name

setSequence

public void setSequence(Sequence sequence,
                        boolean generatedAlways)

Set the sequence to generate the value.

Parameters:

sequence - the sequence

generatedAlways - whether the value of the sequence is always used

getSequence

public Sequence getSequence()

getSelectivity

public int getSelectivity()

Get the selectivity of the column. Selectivity 100 means values are unique, 10 means every distinct value appears 10 times on average.

Returns:

the selectivity

setSelectivity

public void setSelectivity(int selectivity)

Set the new selectivity of a column.

Parameters:

selectivity - the new value

getDefaultSQL

public java.lang.String getDefaultSQL()

Specified by:

getDefaultSQL in interface ColumnTemplate

getOnUpdateSQL

public java.lang.String getOnUpdateSQL()

Specified by:

getOnUpdateSQL in interface ColumnTemplate

setComment

public void setComment(java.lang.String comment)

getComment

public java.lang.String getComment()

setPrimaryKey

public void setPrimaryKey(boolean primaryKey)

isPrimaryKey

public boolean isPrimaryKey()

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

isWideningConversion

public boolean isWideningConversion(Column newColumn)

Check whether the new column is of the same type and not more restricted than this column.

Parameters:

newColumn - the new (target) column

Returns:

true if the new column is compatible

copy

public void copy(Column source)

Copy the data of the source column into the current column.

Parameters:

source - the source column