Package org.h2.table

Class TableFilter

java.lang.Object
org.h2.table.TableFilter
All Implemented Interfaces:
ColumnResolver
public class TableFilter extends Object implements ColumnResolver
A table filter represents a table that is used in a query. There is one such object whenever a table (or view) is used in a query. For example the following query has 2 table filters: SELECT * FROM TEST T1, TEST T2.

  • Field Details

    • ORDER_IN_FROM_COMPARATOR

      public static final Comparator<TableFilter> ORDER_IN_FROM_COMPARATOR
      Comparator that uses order in FROM clause as a sort key.

    • joinOuterIndirect

      protected boolean joinOuterIndirect
      Whether this is a direct or indirect (nested) outer join

  • Constructor Details

    • TableFilter

      public TableFilter(SessionLocal session, Table table, String alias, boolean rightsChecked, Select select, int orderInFrom, IndexHints indexHints)
      Create a new table filter object.
      Parameters:
      session - the session
      table - the table from where to read data
      alias - the alias name
      rightsChecked - true if rights are already checked
      select - the select statement
      orderInFrom - original order number (index) of this table filter in
      indexHints - the index hints to be used by the query planner

  • Method Details

    • getOrderInFrom

      public int getOrderInFrom()
      Get the order number (index) of this table filter in the "from" clause of the query.
      Returns:
      the index (0, 1, 2,...)

    • getSelect

      public Select getSelect()
      Description copied from interface: ColumnResolver
      Get the select statement.
      Specified by:
      getSelect in interface ColumnResolver
      Returns:
      the select statement

    • getTable

      public Table getTable()

    • lock

      public void lock(SessionLocal s)
      Lock the table. This will also lock joined tables.
      Parameters:
      s - the session

    • getBestPlanItem

      public PlanItem getBestPlanItem(SessionLocal s, TableFilter[] filters, int filter, AllColumnsForPlan allColumnsSet, boolean isSelectCommand)
      Get the best plan item (index, cost) to use for the current join order.
      Parameters:
      s - the session
      filters - all joined table filters
      filter - the current table filter index
      allColumnsSet - the set of all columns
      Returns:
      the best plan item

    • setPlanItem

      public void setPlanItem(PlanItem item)
      Set what plan item (index, cost, masks) to use.
      Parameters:
      item - the plan item

    • prepare

      public void prepare()
      Prepare reading rows. This method will remove all index conditions that can not be used, and optimize the conditions.

    • startQuery

      public void startQuery(SessionLocal s)
      Start the query. This will reset the scan counts.
      Parameters:
      s - the session

    • reset

      public void reset()
      Reset to the current position.

    • next

      public boolean next()
      Check if there are more rows to read.
      Returns:
      true if there are

    • isNullRow

      public boolean isNullRow()

    • setNullRow

      protected void setNullRow()
      Set the state of this and all nested tables to the NULL row.

    • get

      public Row get()
      Get the current row.
      Returns:
      the current row, or null

    • set

      public void set(Row current)
      Set the current row.
      Parameters:
      current - the current row

    • getTableAlias

      public String getTableAlias()
      Get the table alias name. If no alias is specified, the table name is returned.
      Specified by:
      getTableAlias in interface ColumnResolver
      Returns:
      the alias name

    • addIndexCondition

      public void addIndexCondition(IndexCondition condition)
      Add an index condition.
      Parameters:
      condition - the index condition

    • addFilterCondition

      public void addFilterCondition(Expression condition, boolean isJoin)
      Add a filter condition.
      Parameters:
      condition - the condition
      isJoin - if this is in fact a join condition

    • addJoin

      public void addJoin(TableFilter filter, boolean outer, Expression on)
      Add a joined table.
      Parameters:
      filter - the joined table filter
      outer - if this is an outer join
      on - the join condition

    • setNestedJoin

      public void setNestedJoin(TableFilter filter)
      Set a nested joined table.
      Parameters:
      filter - the joined table filter

    • addFilter

      public void addFilter(Expression on)
      Add the join condition.
      Parameters:
      on - the condition

    • mapColumns

      public void mapColumns(ColumnResolver resolver, int level, boolean outer)
      Map the columns to the given column resolver.
      Parameters:
      resolver - the resolver
      level - the subquery level (0 is the top level query, 1 is the first subquery level)
      outer - whether this method was called from the outer query

    • createIndexConditions

      public void createIndexConditions()
      Create the index conditions for this filter if needed.

    • getJoin

      public TableFilter getJoin()

    • isJoinOuter

      public boolean isJoinOuter()
      Whether this is an outer joined table.
      Returns:
      true if it is

    • isJoinOuterIndirect

      public boolean isJoinOuterIndirect()
      Whether this is indirectly an outer joined table (nested within an inner join).
      Returns:
      true if it is

    • getPlanSQL

      public StringBuilder getPlanSQL(StringBuilder builder, boolean isJoin, int sqlFlags)
      Get the query execution plan text to use for this table filter and append it to the specified builder.
      Parameters:
      builder - string builder to append to
      isJoin - if this is a joined table
      sqlFlags - formatting flags
      Returns:
      the specified builder

    • getMasks

      public int[] getMasks()

    • getIndex

      public Index getIndex()

    • setIndex

      public void setIndex(Index index, boolean reverse)

    • setUsed

      public void setUsed(boolean used)

    • isUsed

      public boolean isUsed()

    • removeJoin

      public void removeJoin()
      Remove the joined table

    • getJoinCondition

      public Expression getJoinCondition()

    • removeJoinCondition

      public void removeJoinCondition()
      Remove the join condition.

    • getFilterCondition

      public Expression getFilterCondition()

    • removeFilterCondition

      public void removeFilterCondition()
      Remove the filter condition.

    • setFullCondition

      public void setFullCondition(Expression condition)

    • setEvaluatable

      public void setEvaluatable(TableFilter filter, boolean b)
      Update the filter and join conditions of this and all joined tables with the information that the given table filter and all nested filter can now return rows or not.
      Parameters:
      filter - the table filter
      b - the new flag

    • setEvaluatable

      public void setEvaluatable(boolean evaluatable)

    • getSchemaName

      public String getSchemaName()
      Description copied from interface: ColumnResolver
      Get the schema name or null.
      Specified by:
      getSchemaName in interface ColumnResolver
      Returns:
      the schema name or null

    • getColumns

      public Column[] getColumns()
      Description copied from interface: ColumnResolver
      Get the column list.
      Specified by:
      getColumns in interface ColumnResolver
      Returns:
      the column list

    • findColumn

      public Column findColumn(String name)
      Description copied from interface: ColumnResolver
      Get the column with the specified name.
      Specified by:
      findColumn in interface ColumnResolver
      Parameters:
      name - the column name, must be a derived name if this column resolver has a derived column list
      Returns:
      the column with the specified name, or null

    • getColumnName

      public String getColumnName(Column column)
      Description copied from interface: ColumnResolver
      Get the name of the specified column.
      Specified by:
      getColumnName in interface ColumnResolver
      Parameters:
      column - column
      Returns:
      column name

    • hasDerivedColumnList

      public boolean hasDerivedColumnList()
      Description copied from interface: ColumnResolver
      Returns whether this column resolver has a derived column list.
      Specified by:
      hasDerivedColumnList in interface ColumnResolver
      Returns:
      true if this column resolver has a derived column list, false otherwise

    • getColumn

      public Column getColumn(String columnName, boolean ifExists)
      Get the column with the given name.
      Parameters:
      columnName - the column name
      ifExists - if true return null if column does not exist
      Returns:
      the column
      Throws:
      DbException - if the column was not found and ifExists is false

    • getSystemColumns

      public Column[] getSystemColumns()
      Get the system columns that this table understands. This is used for compatibility with other databases. The columns are only returned if the current mode supports system columns.
      Specified by:
      getSystemColumns in interface ColumnResolver
      Returns:
      the system columns

    • getRowIdColumn

      public Column getRowIdColumn()
      Description copied from interface: ColumnResolver
      Get the row id pseudo column, if there is one.
      Specified by:
      getRowIdColumn in interface ColumnResolver
      Returns:
      the row id column or null

    • getValue

      public Value getValue(Column column)
      Description copied from interface: ColumnResolver
      Get the value for the given column.
      Specified by:
      getValue in interface ColumnResolver
      Parameters:
      column - the column
      Returns:
      the value

    • getTableFilter

      public TableFilter getTableFilter()
      Description copied from interface: ColumnResolver
      Get the table filter.
      Specified by:
      getTableFilter in interface ColumnResolver
      Returns:
      the table filter

    • setAlias

      public void setAlias(String alias)

    • setDerivedColumns

      public void setDerivedColumns(ArrayList<String> derivedColumnNames)
      Set derived column list.
      Parameters:
      derivedColumnNames - names of derived columns

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • addCommonJoinColumns

      public void addCommonJoinColumns(Column leftColumn, Column replacementColumn, TableFilter replacementFilter)
      Add a column to the common join column list for a left table filter.
      Parameters:
      leftColumn - the column on the left side
      replacementColumn - the column to use instead, may be the same as column on the left side
      replacementFilter - the table filter for replacement columns

    • addCommonJoinColumnToExclude

      public void addCommonJoinColumnToExclude(Column columnToExclude)
      Add an excluded column to the common join column list.
      Parameters:
      columnToExclude - the column to exclude

    • getCommonJoinColumns

      public LinkedHashMap<Column,Column> getCommonJoinColumns()
      Returns common join columns map.
      Returns:
      common join columns map, or null

    • getCommonJoinColumnsFilter

      public TableFilter getCommonJoinColumnsFilter()
      Returns common join columns table filter.
      Returns:
      common join columns table filter, or null

    • isCommonJoinColumnToExclude

      public boolean isCommonJoinColumnToExclude(Column c)
      Check if the given column is an excluded common join column.
      Parameters:
      c - the column to check
      Returns:
      true if this is an excluded common join column

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • getNestedJoin

      public TableFilter getNestedJoin()

    • visit

      public void visit(TableFilter.TableFilterVisitor visitor)
      Visit this and all joined or nested table filters.
      Parameters:
      visitor - the visitor

    • isEvaluatable

      public boolean isEvaluatable()

    • getSession

      public SessionLocal getSession()

    • getIndexHints

      public IndexHints getIndexHints()

    • hasFromClause

      public boolean hasFromClause()
      Returns whether this is a table filter with implicit DUAL table for a SELECT without a FROM clause.
      Returns:
      false if this is a table filter with implicit DUAL table, true otherwise