/*
* Copyright 2004-2013 H2 Group. Multiple-Licensed under the H2 License,
* Version 1.0, and under the Eclipse Public License, Version 1.0
* (http://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.lealone.dbobject.table;
import java.util.ArrayList;
import org.lealone.command.Prepared;
import org.lealone.command.dml.Query;
import org.lealone.constant.Constants;
import org.lealone.constant.ErrorCode;
import org.lealone.dbobject.Schema;
import org.lealone.dbobject.User;
import org.lealone.dbobject.index.Index;
import org.lealone.dbobject.index.IndexType;
import org.lealone.dbobject.index.ViewIndex;
import org.lealone.engine.Session;
import org.lealone.expression.Expression;
import org.lealone.expression.ExpressionVisitor;
import org.lealone.expression.Parameter;
import org.lealone.message.DbException;
import org.lealone.result.LocalResult;
import org.lealone.result.ResultInterface;
import org.lealone.result.Row;
import org.lealone.result.SortOrder;
import org.lealone.util.IntArray;
import org.lealone.util.New;
import org.lealone.util.SmallLRUCache;
import org.lealone.util.StatementBuilder;
import org.lealone.util.StringUtils;
import org.lealone.util.SynchronizedVerifier;
import org.lealone.util.Utils;
import org.lealone.value.Value;
/**
* A view is a virtual table that is defined by a query.
*/
public class TableView extends Table {
private static final long ROW_COUNT_APPROXIMATION = 100;
private String querySQL;
private ArrayList<Table> tables;
private String[] columnNames;
private Query viewQuery;
private ViewIndex index;
private boolean recursive;
private DbException createException;
private final SmallLRUCache<IntArray, ViewIndex> indexCache = SmallLRUCache.newInstance(Constants.VIEW_INDEX_CACHE_SIZE);
private long lastModificationCheck;
private long maxDataModificationId;
private User owner;
private Query topQuery;
private LocalResult recursiveResult;
private boolean tableExpression;
public TableView(Schema schema, int id, String name, String querySQL, ArrayList<Parameter> params, String[] columnNames,
Session session, boolean recursive) {
super(schema, id, name, false, true);
init(querySQL, params, columnNames, session, recursive);
}
/**
* Try to replace the SQL statement of the view and re-compile this and all
* dependent views.
*
* @param querySQL the SQL statement
* @param columnNames the column names
* @param session the session
* @param recursive whether this is a recursive view
* @param force if errors should be ignored
*/
public void replace(String querySQL, String[] columnNames, Session session, boolean recursive, boolean force) {
String oldQuerySQL = this.querySQL;
String[] oldColumnNames = this.columnNames;
boolean oldRecursive = this.recursive;
init(querySQL, null, columnNames, session, recursive);
DbException e = recompile(session, force);
if (e != null) {
init(oldQuerySQL, null, oldColumnNames, session, oldRecursive);
recompile(session, true);
throw e;
}
}
private synchronized void init(String querySQL, ArrayList<Parameter> params, String[] columnNames, Session session,
boolean recursive) {
this.querySQL = querySQL;
this.columnNames = columnNames;
this.recursive = recursive;
index = new ViewIndex(this, querySQL, params, recursive);
SynchronizedVerifier.check(indexCache);
indexCache.clear();
initColumnsAndTables(session);
}
private static Query compileViewQuery(Session session, String sql) {
Prepared p = session.prepare(sql);
if (!(p instanceof Query)) {
throw DbException.getSyntaxError(sql, 0);
}
return (Query) p;
}
/**
* Re-compile the view query and all views that depend on this object.
*
* @param session the session
* @param force if exceptions should be ignored
* @return the exception if re-compiling this or any dependent view failed
* (only when force is disabled)
*/
public synchronized DbException recompile(Session session, boolean force) {
try {
compileViewQuery(session, querySQL);
} catch (DbException e) {
if (!force) {
return e;
}
}
ArrayList<TableView> views = getViews();
if (views != null) {
views = New.arrayList(views);
}
SynchronizedVerifier.check(indexCache);
indexCache.clear();
initColumnsAndTables(session);
if (views != null) {
for (TableView v : views) {
DbException e = v.recompile(session, force);
if (e != null && !force) {
return e;
}
}
}
return force ? null : createException;
}
private void initColumnsAndTables(Session session) {
Column[] cols;
removeViewFromTables();
try {
Query query = compileViewQuery(session, querySQL);
this.querySQL = query.getPlanSQL();
tables = New.arrayList(query.getTables());
ArrayList<Expression> expressions = query.getExpressions();
ArrayList<Column> list = New.arrayList();
for (int i = 0, count = query.getColumnCount(); i < count; i++) {
Expression expr = expressions.get(i);
String name = null;
if (columnNames != null && columnNames.length > i) {
name = columnNames[i];
}
if (name == null) {
name = expr.getAlias();
}
int type = expr.getType();
long precision = expr.getPrecision();
int scale = expr.getScale();
int displaySize = expr.getDisplaySize();
Column col = new Column(name, type, precision, scale, displaySize);
col.setTable(this, i);
list.add(col);
}
cols = new Column[list.size()];
list.toArray(cols);
createException = null;
viewQuery = query;
} catch (DbException e) {
e.addSQL(getCreateSQL());
createException = e;
// if it can't be compiled, then it's a 'zero column table'
// this avoids problems when creating the view when opening the
// database
tables = New.arrayList();
cols = new Column[0];
if (recursive && columnNames != null) {
cols = new Column[columnNames.length];
for (int i = 0; i < columnNames.length; i++) {
cols[i] = new Column(columnNames[i], Value.STRING);
}
index.setRecursive(true);
createException = null;
}
}
setColumns(cols);
if (getId() != 0) {
addViewToTables();
}
}
/**
* Check if this view is currently invalid.
*
* @return true if it is
*/
public boolean isInvalid() {
return createException != null;
}
public synchronized PlanItem getBestPlanItem(Session session, int[] masks, SortOrder sortOrder) {
PlanItem item = new PlanItem();
item.cost = index.getCost(session, masks, sortOrder);
IntArray masksArray = new IntArray(masks == null ? Utils.EMPTY_INT_ARRAY : masks);
SynchronizedVerifier.check(indexCache);
ViewIndex i2 = indexCache.get(masksArray);
if (i2 == null || i2.getSession() != session) {
i2 = new ViewIndex(this, index, session, masks);
indexCache.put(masksArray, i2);
}
item.setIndex(i2);
return item;
}
public String getDropSQL() {
return "DROP VIEW IF EXISTS " + getSQL() + " CASCADE";
}
public String getCreateSQLForCopy(Table table, String quotedName) {
return getCreateSQL(false, true, quotedName);
}
public String getCreateSQL() {
return getCreateSQL(false, true);
}
/**
* Generate "CREATE" SQL statement for the view.
*
* @param orReplace if true, then include the OR REPLACE clause
* @param force if true, then include the FORCE clause
* @return the SQL statement
*/
public String getCreateSQL(boolean orReplace, boolean force) {
return getCreateSQL(orReplace, force, getSQL());
}
private String getCreateSQL(boolean orReplace, boolean force, String quotedName) {
StatementBuilder buff = new StatementBuilder("CREATE ");
if (orReplace) {
buff.append("OR REPLACE ");
}
if (force) {
buff.append("FORCE ");
}
buff.append("VIEW ");
buff.append(quotedName);
if (comment != null) {
buff.append(" COMMENT ").append(StringUtils.quoteStringSQL(comment));
}
if (columns != null && columns.length > 0) {
buff.append('(');
for (Column c : columns) {
buff.appendExceptFirst(", ");
buff.append(c.getSQL());
}
buff.append(')');
} else if (columnNames != null) {
buff.append('(');
for (String n : columnNames) {
buff.appendExceptFirst(", ");
buff.append(n);
}
buff.append(')');
}
return buff.append(" AS\n").append(querySQL).toString();
}
public void checkRename() {
// ok
}
public void lock(Session session, boolean exclusive, boolean force) {
// exclusive lock means: the view will be dropped
}
public void close(Session session) {
// nothing to do
}
public void unlock(Session s) {
// nothing to do
}
public boolean isLockedExclusively() {
return false;
}
public Index addIndex(Session session, String indexName, int indexId, IndexColumn[] cols, IndexType indexType,
boolean create, String indexComment) {
throw DbException.getUnsupportedException("VIEW");
}
public void removeRow(Session session, Row row) {
throw DbException.getUnsupportedException("VIEW");
}
public void addRow(Session session, Row row) {
throw DbException.getUnsupportedException("VIEW");
}
public void checkSupportAlter() {
throw DbException.getUnsupportedException("VIEW");
}
public void truncate(Session session) {
throw DbException.getUnsupportedException("VIEW");
}
public long getRowCount(Session session) {
throw DbException.throwInternalError();
}
public boolean canGetRowCount() {
// TODO view: could get the row count, but not that easy
return false;
}
public boolean canDrop() {
return true;
}
public String getTableType() {
return Table.VIEW;
}
public void removeChildrenAndResources(Session session) {
removeViewFromTables();
super.removeChildrenAndResources(session);
database.removeMeta(session, getId());
querySQL = null;
index = null;
invalidate();
}
public String getSQL() {
if (isTemporary()) {
return "(\n" + StringUtils.indent(querySQL) + ")";
}
return super.getSQL();
}
public String getQuery() {
return querySQL;
}
public Index getScanIndex(Session session) {
if (createException != null) {
String msg = createException.getMessage();
throw DbException.get(ErrorCode.VIEW_IS_INVALID_2, createException, getSQL(), msg);
}
PlanItem item = getBestPlanItem(session, null, null);
return item.getIndex();
}
public ArrayList<Index> getIndexes() {
return null;
}
public long getMaxDataModificationId() {
if (createException != null) {
return Long.MAX_VALUE;
}
if (viewQuery == null) {
return Long.MAX_VALUE;
}
// if nothing was modified in the database since the last check, and the
// last is known, then we don't need to check again
// this speeds up nested views
long dbMod = database.getModificationDataId();
if (dbMod > lastModificationCheck && maxDataModificationId <= dbMod) {
maxDataModificationId = viewQuery.getMaxDataModificationId();
lastModificationCheck = dbMod;
}
return maxDataModificationId;
}
public Index getUniqueIndex() {
return null;
}
private void removeViewFromTables() {
if (tables != null) {
for (Table t : tables) {
t.removeView(this);
}
tables.clear();
}
}
private void addViewToTables() {
for (Table t : tables) {
t.addView(this);
}
}
private void setOwner(User owner) {
this.owner = owner;
}
public User getOwner() {
return owner;
}
/**
* Create a temporary view out of the given query.
*
* @param session the session
* @param owner the owner of the query
* @param name the view name
* @param query the query
* @param topQuery the top level query
* @return the view table
*/
public static TableView createTempView(Session session, User owner, String name, Query query, Query topQuery) {
Schema mainSchema = session.getDatabase().getSchema(Constants.SCHEMA_MAIN);
String querySQL = query.getPlanSQL();
TableView v = new TableView(mainSchema, 0, name, querySQL, query.getParameters(), null, session, false);
if (v.createException != null) {
throw v.createException;
}
v.setTopQuery(topQuery);
v.setOwner(owner);
v.setTemporary(true);
return v;
}
private void setTopQuery(Query topQuery) {
this.topQuery = topQuery;
}
public long getRowCountApproximation() {
return ROW_COUNT_APPROXIMATION;
}
public long getDiskSpaceUsed() {
return 0;
}
public int getParameterOffset() {
return topQuery == null ? 0 : topQuery.getParameters().size();
}
public boolean isDeterministic() {
if (recursive || viewQuery == null) {
return false;
}
return viewQuery.isEverything(ExpressionVisitor.DETERMINISTIC_VISITOR);
}
public void setRecursiveResult(LocalResult value) {
if (recursiveResult != null) {
recursiveResult.close();
}
this.recursiveResult = value;
}
public ResultInterface getRecursiveResult() {
return recursiveResult;
}
public void setTableExpression(boolean tableExpression) {
this.tableExpression = tableExpression;
}
public boolean isTableExpression() {
return tableExpression;
}
public String getTableName() {
for (Table t : tables) {
if (t instanceof TableView) {
return ((TableView) t).getTableName();
} else {
return t.getName();
}
}
return getName();
}
@Override
public boolean isDistributed() {
for (Table t : tables) {
if (t instanceof TableView) {
return ((TableView) t).isDistributed();
} else {
return t.isDistributed();
}
}
return super.isDistributed();
}
}