Column (H2 Database Engine 2.0.0 API)

java.lang.Object
- org.h2.table.Column

所有已实现的接口:

ColumnTemplate, HasSQL, Typed
```
public final class Column
extends Object
implements HasSQL, Typed, ColumnTemplate
```
This class represents a column in a table.

字段概要

字段
限定符和类型	字段和说明
`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 String`	`ROWID` The name of the rowid pseudo column.

从接口继承的字段 org.h2.util.HasSQL
ADD_PLAN_INFORMATION, DEFAULT_SQL_FLAGS, NO_CASTS, QUOTE_ONLY_WHEN_REQUIRED, REPLACE_LOBS_FOR_TRACE, TRACE_SQL_FLAGS

构造器概要

构造器
构造器和说明

Column(String name, TypeInfo type)

Column(String name, TypeInfo type, Table table, int columnId)

构造器
构造器和说明
`Column(String name, TypeInfo type)`
`Column(String name, TypeInfo type, Table table, int columnId)`

方法概要

所有方法静态方法实例方法具体方法
限定符和类型	方法和说明
`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(Object o)`
`Column`	`getClone()`
`int`	`getColumnId()`
`String`	`getComment()`
`String`	`getCreateSQL()`
`String`	`getCreateSQL(boolean forMeta)` Get this columns part of CREATE TABLE SQL statement.
`String`	`getCreateSQLWithoutName()`
`Expression`	`getDefaultExpression()`
`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.
`String`	`getName()`
`Expression`	`getOnUpdateExpression()`
`String`	`getOnUpdateSQL()`
`int`	`getSelectivity()` Get the selectivity of the column.
`Sequence`	`getSequence()`
`String`	`getSQL(int sqlFlags)` Get the SQL statement of this expression.
`StringBuilder`	`getSQL(StringBuilder builder, int sqlFlags)` Appends the SQL statement of this object to the specified builder.
`StringBuilder`	`getSQLWithTable(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(String newName)` Rename the column.
`void`	`setComment(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)`
`String`	`toString()`
`static StringBuilder`	`writeColumns(StringBuilder builder, Column[] columns, int sqlFlags)` Appends the specified columns to the specified builder.
`static StringBuilder`	`writeColumns(StringBuilder builder, Column[] columns, String separator, String suffix, int sqlFlags)` Appends the specified columns to the specified builder.

从类继承的方法 java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

从接口继承的方法 org.h2.util.HasSQL
getTraceSQL

- 字段详细资料
  - ROWID
```
public static final String ROWID
```
    The name of the rowid pseudo column.
    
    另请参阅:
    
    常量字段值
  - NOT_NULLABLE
```
public static final int NOT_NULLABLE
```
    This column is not nullable.
    
    另请参阅:
    
    常量字段值
  - NULLABLE
```
public static final int NULLABLE
```
    This column is nullable.
    
    另请参阅:
    
    常量字段值
  - NULLABLE_UNKNOWN
```
public static final int NULLABLE_UNKNOWN
```
    It is not know whether this column is nullable.
    
    另请参阅:
    
    常量字段值
- 构造器详细资料
  - Column
```
public Column(String name,
              TypeInfo type)
```
  - Column
```
public Column(String name,
              TypeInfo type,
              Table table,
              int columnId)
```
- 方法详细资料
  - writeColumns
```
public static StringBuilder writeColumns(StringBuilder builder,
                                         Column[] columns,
                                         int sqlFlags)
```
    Appends the specified columns to the specified builder.
    
    参数:
    
    builder - string builder
    
    columns - columns
    
    sqlFlags - formatting flags
    
    返回:
    
    the specified string builder
  - writeColumns
```
public static StringBuilder writeColumns(StringBuilder builder,
                                         Column[] columns,
                                         String separator,
                                         String suffix,
                                         int sqlFlags)
```
    Appends the specified columns to the specified builder.
    
    参数:
    
    builder - string builder
    
    columns - columns
    
    separator - separator
    
    suffix - additional SQL to append after each column
    
    sqlFlags - formatting flags
    
    返回:
    
    the specified string builder
  - equals
```
public boolean equals(Object o)
```
    覆盖:
    
    equals 在类中 Object
  - hashCode
```
public int hashCode()
```
    覆盖:
    
    hashCode 在类中 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.
    
    参数:
    
    provider - the cast information provider
    
    v - the value
    
    返回:
    
    the value
  - isIdentity
```
public boolean isIdentity()
```
    Returns whether this column is an identity column.
    
    返回:
    
    whether this column is an identity column
  - isGenerated
```
public boolean isGenerated()
```
    Returns whether this column is a generated column.
    
    返回:
    
    whether this column is a generated column
  - isGeneratedAlways
```
public boolean isGeneratedAlways()
```
    Returns whether this column is a generated column or always generated identity column.
    
    返回:
    
    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.
    
    参数:
    
    expression - the computed expression
  - setTable
```
public void setTable(Table table,
                     int columnId)
```
    Set the table and column id.
    
    参数:
    
    table - the table
    
    columnId - the column index
  - getTable
```
public Table getTable()
```
  - setDefaultExpression
```
public void setDefaultExpression(SessionLocal session,
                                 Expression defaultExpression)
```
    从接口复制的说明: ColumnTemplate
    
    Set the default expression.
    
    指定者:
    
    setDefaultExpression 在接口中 ColumnTemplate
    
    参数:
    
    session - the session
    
    defaultExpression - the default expression
  - setOnUpdateExpression
```
public void setOnUpdateExpression(SessionLocal session,
                                  Expression onUpdateExpression)
```
    从接口复制的说明: ColumnTemplate
    
    Set the on update expression.
    
    指定者:
    
    setOnUpdateExpression 在接口中 ColumnTemplate
    
    参数:
    
    session - the session
    
    onUpdateExpression - the on update expression
  - getColumnId
```
public int getColumnId()
```
  - getSQL
```
public String getSQL(int sqlFlags)
```
    从接口复制的说明: HasSQL
    
    Get the SQL statement of this expression. This may not always be the original SQL statement, specially after optimization.
    
    指定者:
    
    getSQL 在接口中 HasSQL
    
    参数:
    
    sqlFlags - formatting flags
    
    返回:
    
    the SQL statement
  - getSQL
```
public StringBuilder getSQL(StringBuilder builder,
                            int sqlFlags)
```
    从接口复制的说明: HasSQL
    
    Appends the SQL statement of this object to the specified builder.
    
    指定者:
    
    getSQL 在接口中 HasSQL
    
    参数:
    
    builder - string builder
    
    sqlFlags - formatting flags
    
    返回:
    
    the specified string builder
  - getSQLWithTable
```
public StringBuilder getSQLWithTable(StringBuilder builder,
                                     int sqlFlags)
```
    Appends the table name and column name to the specified builder.
    
    参数:
    
    builder - the string builder
    
    sqlFlags - formatting flags
    
    返回:
    
    the specified string builder
  - getName
```
public String getName()
```
  - getType
```
public TypeInfo getType()
```
    从接口复制的说明: Typed
    
    Returns the data type.
    
    指定者:
    
    getType 在接口中 Typed
    
    返回:
    
    the data type
  - setNullable
```
public void setNullable(boolean b)
```
  - getVisible
```
public boolean getVisible()
```
  - setVisible
```
public void setVisible(boolean b)
```
  - getDomain
```
public Domain getDomain()
```
    指定者:
    
    getDomain 在接口中 ColumnTemplate
  - setDomain
```
public void setDomain(Domain domain)
```
    指定者:
    
    setDomain 在接口中 ColumnTemplate
  - isRowId
```
public boolean isRowId()
```
    Returns whether this column is a row identity column.
    
    返回:
    
    true for _ROWID_ column, false otherwise
  - setRowId
```
public void setRowId(boolean rowId)
```
    Set row identity flag.
    
    参数:
    
    rowId - true _ROWID_ column, false otherwise
  - initializeSequence
```
public void initializeSequence(SessionLocal session,
                               Schema schema,
                               int id,
                               boolean temporary)
```
    Initialize the sequence for this column.
    
    参数:
    
    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)
```
    从接口复制的说明: ColumnTemplate
    
    Prepare all expressions of this column or domain.
    
    指定者:
    
    prepareExpressions 在接口中 ColumnTemplate
    
    参数:
    
    session - the session
  - getCreateSQLWithoutName
```
public String getCreateSQLWithoutName()
```
  - getCreateSQL
```
public String getCreateSQL()
```
  - getCreateSQL
```
public String getCreateSQL(boolean forMeta)
```
    Get this columns part of CREATE TABLE SQL statement.
    
    参数:
    
    forMeta - whether this is for the metadata table
    
    返回:
    
    the SQL statement
  - isNullable
```
public boolean isNullable()
```
  - getDefaultExpression
```
public Expression getDefaultExpression()
```
    指定者:
    
    getDefaultExpression 在接口中 ColumnTemplate
  - getEffectiveDefaultExpression
```
public Expression getEffectiveDefaultExpression()
```
    指定者:
    
    getEffectiveDefaultExpression 在接口中 ColumnTemplate
  - getOnUpdateExpression
```
public Expression getOnUpdateExpression()
```
    指定者:
    
    getOnUpdateExpression 在接口中 ColumnTemplate
  - getEffectiveOnUpdateExpression
```
public Expression getEffectiveOnUpdateExpression()
```
    指定者:
    
    getEffectiveOnUpdateExpression 在接口中 ColumnTemplate
  - hasIdentityOptions
```
public boolean hasIdentityOptions()
```
    Whether the column has any identity options.
    
    返回:
    
    true if yes
  - setIdentityOptions
```
public void setIdentityOptions(SequenceOptions identityOptions,
                               boolean generatedAlways)
```
    Set the identity options of this column.
    
    参数:
    
    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.
    
    返回:
    
    identity column options, or null
  - setDefaultOnNull
```
public void setDefaultOnNull(boolean defaultOnNull)
```
  - isDefaultOnNull
```
public boolean isDefaultOnNull()
```
  - rename
```
public void rename(String newName)
```
    Rename the column. This method will only set the column name to the new value.
    
    参数:
    
    newName - the new column name
  - setSequence
```
public void setSequence(Sequence sequence,
                        boolean generatedAlways)
```
    Set the sequence to generate the value.
    
    参数:
    
    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.
    
    返回:
    
    the selectivity
  - setSelectivity
```
public void setSelectivity(int selectivity)
```
    Set the new selectivity of a column.
    
    参数:
    
    selectivity - the new value
  - getDefaultSQL
```
public String getDefaultSQL()
```
    指定者:
    
    getDefaultSQL 在接口中 ColumnTemplate
  - getOnUpdateSQL
```
public String getOnUpdateSQL()
```
    指定者:
    
    getOnUpdateSQL 在接口中 ColumnTemplate
  - setComment
```
public void setComment(String comment)
```
  - getComment
```
public String getComment()
```
  - setPrimaryKey
```
public void setPrimaryKey(boolean primaryKey)
```
  - isPrimaryKey
```
public boolean isPrimaryKey()
```
  - toString
```
public String toString()
```
    覆盖:
    
    toString 在类中 Object
  - isWideningConversion
```
public boolean isWideningConversion(Column newColumn)
```
    Check whether the new column is of the same type and not more restricted than this column.
    
    参数:
    
    newColumn - the new (target) column
    
    返回:
    
    true if the new column is compatible
  - copy
```
public void copy(Column source)
```
    Copy the data of the source column into the current column.
    
    参数:
    
    source - the source column

类 Column

字段概要

从接口继承的字段 org.h2.util.HasSQL

构造器概要

方法概要

从类继承的方法 java.lang.Object

从接口继承的方法 org.h2.util.HasSQL

字段详细资料

ROWID

NOT_NULLABLE

NULLABLE

NULLABLE_UNKNOWN

构造器详细资料

Column

Column

方法详细资料

writeColumns

writeColumns

equals

hashCode

getClone

convert

isIdentity

isGenerated

isGeneratedAlways

setGeneratedExpression

setTable

getTable

setDefaultExpression

setOnUpdateExpression

getColumnId

getSQL

getSQL

getSQLWithTable

getName

getType

setNullable

getVisible

setVisible

getDomain

setDomain

isRowId

setRowId

initializeSequence

prepareExpressions

getCreateSQLWithoutName

getCreateSQL

getCreateSQL

isNullable

getDefaultExpression

getEffectiveDefaultExpression

getOnUpdateExpression

getEffectiveOnUpdateExpression

hasIdentityOptions

setIdentityOptions

getIdentityOptions

setDefaultOnNull

isDefaultOnNull

rename

setSequence

getSequence

getSelectivity

setSelectivity

getDefaultSQL

getOnUpdateSQL

setComment

getComment

setPrimaryKey

isPrimaryKey

toString

isWideningConversion

copy