import com.alibaba.druid.sql.SQLUtils; //导入依赖的package包/类
protected void setLimitIFChange(SQLStatement stmt, RouteResultset rrs, SchemaConfig schema, SQLBinaryOpExpr one, int firstrownum, int lastrownum)
{
	rrs.setLimitStart(firstrownum);
	rrs.setLimitSize(lastrownum - firstrownum);
	LayerCachePool tableId2DataNodeCache = (LayerCachePool) MycatServer.getInstance().getCacheService().getCachePool("TableID2DataNodeCache");
	try
	{
		tryRoute(schema, rrs, tableId2DataNodeCache);
	} catch (SQLNonTransientException e)
	{
		throw new RuntimeException(e);
	}
	if (isNeedChangeLimit(rrs))
	{
		one.setRight(new SQLIntegerExpr(0));
           String curentDbType ="db2".equalsIgnoreCase(this.getCurentDbType())?"oracle":getCurentDbType();
           String sql =   SQLUtils.toSQLString(stmt, curentDbType);;
		rrs.changeNodeSqlAfterAddLimit(schema,getCurentDbType(), sql,0,lastrownum, false);
		//设置改写后的sql
		getCtx().setSql(sql);
	}
}
 

import com.alibaba.druid.sql.SQLUtils; //导入依赖的package包/类
/**
 * only for show columns
 */
public boolean isUNI(String columnName) {
    for (SQLTableElement element : this.tableElementList) {
        if (element instanceof MySqlUnique) {
            MySqlUnique unique = (MySqlUnique) element;

            if (unique.getColumns().size() == 0) {
                continue;
            }

            SQLExpr column = unique.getColumns().get(0).getExpr();
            if (column instanceof SQLIdentifierExpr
                    && SQLUtils.nameEquals(columnName, ((SQLIdentifierExpr) column).getName())) {
                return unique.columns.size() == 1;
            } else if (column instanceof SQLMethodInvokeExpr
                    && SQLUtils.nameEquals(((SQLMethodInvokeExpr) column).getMethodName(), columnName)) {
                return true;
            }
        }
    }
    return false;
}
 

import com.alibaba.druid.sql.SQLUtils; //导入依赖的package包/类
public boolean isReferenced(String tableName) {
    if (tableName == null) {
        return false;
    }

    tableName = SQLUtils.normalize(tableName);

    for (SQLTableElement element : this.tableElementList) {
        if (element instanceof SQLForeignKeyConstraint) {
            SQLForeignKeyConstraint fk = (SQLForeignKeyConstraint) element;
            String refTableName = fk.getReferencedTableName().getSimpleName();

            if (SQLUtils.nameEquals(tableName, refTableName)) {
                return true;
            }
        }
    }

    return false;
}
 

import com.alibaba.druid.sql.SQLUtils; //导入依赖的package包/类
public boolean apply(SQLDropIndexStatement x) {
    long indexNameHashCode64 = x.getIndexName().nameHashCode64();

    for (int i = tableElementList.size() - 1; i >= 0; i--) {
        SQLTableElement e = tableElementList.get(i);
        if (e instanceof SQLUniqueConstraint) {
            SQLUniqueConstraint unique = (SQLUniqueConstraint) e;
            if (unique.getName().nameHashCode64() == indexNameHashCode64) {
                tableElementList.remove(i);
                return true;
            }

        } else if (e instanceof MySqlTableIndex) {
            MySqlTableIndex tableIndex = (MySqlTableIndex) e;
            if (SQLUtils.nameEquals(tableIndex.getName(), x.getIndexName())) {
                tableElementList.remove(i);
                return true;
            }
        }
    }
    return false;
}
 

import com.alibaba.druid.sql.SQLUtils; //导入依赖的package包/类
protected int columnIndexOf(SQLName column) {
    if (column == null) {
        return -1;
    }

    String columnName = column.getSimpleName();
    for (int i = tableElementList.size() - 1; i >= 0; --i) {
        SQLTableElement e = tableElementList.get(i);
        if (e instanceof SQLColumnDefinition) {
            if (SQLUtils.nameEquals(columnName, ((SQLColumnDefinition) e).getName().getSimpleName())) {
                return i;
            }
        }
    }

    return -1;
}
 

import com.alibaba.druid.sql.SQLUtils; //导入依赖的package包/类
public boolean applyDropColumn(SQLName columnName) {
    for (int i = columns.size() - 1; i >= 0; i--) {
        SQLExpr expr = columns.get(i).getExpr();
        if (expr instanceof SQLName
                && SQLUtils.nameEquals((SQLName) expr, columnName)) {
            columns.remove(i);
            return true;
        }

        if (expr instanceof SQLMethodInvokeExpr
                && SQLUtils.nameEquals(((SQLMethodInvokeExpr) expr).getMethodName(), columnName.getSimpleName())) {
            columns.remove(i);
            return true;
        }
    }
    return false;
}
 

import com.alibaba.druid.sql.SQLUtils; //导入依赖的package包/类
public boolean match(String owner, String function) {
    if (function == null) {
        return false;
    }

    if (!SQLUtils.nameEquals(function, name)) {
        return false;
    }

    if (owner == null && this.owner == null) {
        return true;
    }

    if (owner == null || this.owner == null) {
        return false;
    }

    if (this.owner instanceof SQLIdentifierExpr) {
        return SQLUtils.nameEquals(((SQLIdentifierExpr) this.owner).name, owner);
    }

    return false;
}
 

import com.alibaba.druid.sql.SQLUtils; //导入依赖的package包/类
public SQLDataType computeDataType() {
    if (SQLUtils.nameEquals("to_date", name)
            || SQLUtils.nameEquals("add_months", name)) {
        return SQLDateExpr.DEFAULT_DATA_TYPE;
    }

    if (parameters.size() == 1) {
        if (SQLUtils.nameEquals("trunc", name)) {
            return parameters.get(0).computeDataType();
        }
    } else if (parameters.size() == 2) {
        SQLExpr param0 = parameters.get(0);
        SQLExpr param1 = parameters.get(1);
        if (SQLUtils.nameEquals("nvl", name) || SQLUtils.nameEquals("ifnull", name)) {
            SQLDataType dataType = param0.computeDataType();
            if (dataType != null) {
                return dataType;
            }

            return param1.computeDataType();
        }
    }
    return null;
}
 

import com.alibaba.druid.sql.SQLUtils; //导入依赖的package包/类
public boolean applyDropColumn(SQLName columnName) {
    for (int i = columns.size() - 1; i >= 0; i--) {
        SQLExpr expr = columns.get(i).getExpr();
        if (expr instanceof SQLName
                && SQLUtils.nameEquals((SQLName) expr, columnName)) {
            columns.remove(i);
            return true;
        }
        if (expr instanceof SQLMethodInvokeExpr
                && SQLUtils.nameEquals(((SQLMethodInvokeExpr) expr).getMethodName(), columnName.getSimpleName())) {
            columns.remove(i);
            return true;
        }
    }
    return false;
}
 

import com.alibaba.druid.sql.SQLUtils; //导入依赖的package包/类
public String computeName() {
    if (tableSource == null) {
        return null;
    }

    SQLExpr expr = tableSource.getExpr();
    if (expr instanceof SQLName) {
        String name = ((SQLName) expr).getSimpleName();
        return SQLUtils.normalize(name);
    }

    return null;
}
 

import com.alibaba.druid.sql.SQLUtils; //导入依赖的package包/类
public String computeAlias() {
    String alias = this.getAlias();
    if (alias == null) {
        if (expr instanceof SQLIdentifierExpr) {
            alias = ((SQLIdentifierExpr) expr).getName();
        } else if (expr instanceof SQLPropertyExpr) {
            alias = ((SQLPropertyExpr) expr).getName();
        }
    }

    return SQLUtils.normalize(alias);
}
 

import com.alibaba.druid.sql.SQLUtils; //导入依赖的package包/类
public String computeAlias() {
    String alias = null;

    if (name instanceof SQLIdentifierExpr) {
        alias = ((SQLIdentifierExpr) name).getName();
    } else if (name instanceof SQLPropertyExpr) {
        alias = ((SQLPropertyExpr) name).getName();
    }

    return SQLUtils.normalize(alias);
}
 

import com.alibaba.druid.sql.SQLUtils; //导入依赖的package包/类
public void simplify() {
    enable = null;
    validate = null;
    rely = null;


    if (this.name instanceof SQLIdentifierExpr) {
        SQLIdentifierExpr identExpr = (SQLIdentifierExpr) this.name;
        String columnName = identExpr.getName();
        String normalized = SQLUtils.normalize(columnName, dbType);
        if (normalized != columnName) {
            this.setName(normalized);
        }
    }
}
 

import com.alibaba.druid.sql.SQLUtils; //导入依赖的package包/类
public boolean containsAlias(String alias) {
    if (SQLUtils.nameEquals(this.alias, alias)) {
        return true;
    }

    if (left != null && left.containsAlias(alias)) {
        return true;
    }

    if (right != null && right.containsAlias(alias)) {
        return true;
    }

    return false;
}
 

import com.alibaba.druid.sql.SQLUtils; //导入依赖的package包/类
public void simplify() {
    if (this.name instanceof SQLIdentifierExpr) {
        SQLIdentifierExpr identExpr = (SQLIdentifierExpr) this.name;
        String columnName = identExpr.getName();

        String normalized = SQLUtils.normalize(columnName, dbType);
        if (columnName != normalized) {
            this.setName(normalized);
        }
    }
}
 

import com.alibaba.druid.sql.SQLUtils; //导入依赖的package包/类
public boolean containsAlias(String alias) {
    if (SQLUtils.nameEquals(this.alias, alias)) {
        return true;
    }

    return false;
}
 

import com.alibaba.druid.sql.SQLUtils; //导入依赖的package包/类
public String computeAlias() {
    String alias = this.getAlias();

    if (alias == null) {
        if (expr instanceof SQLName) {
            alias =((SQLName) expr).getSimpleName();
        }
    }

    return SQLUtils.normalize(alias);
}
 

import com.alibaba.druid.sql.SQLUtils; //导入依赖的package包/类
public String toString() {
    SQLObject parent = this.getParent();
    if (parent instanceof SQLStatement) {
        String dbType = ((SQLStatement) parent).getDbType();
        
        if (dbType != null) {
            return SQLUtils.toSQLString(this, dbType);
        }
    }
    
    return super.toString();
}
 

import com.alibaba.druid.sql.SQLUtils; //导入依赖的package包/类
public boolean containsColumn(String column) {
    for (SQLSelectOrderByItem item : columns) {
        SQLExpr expr = item.getExpr();
        if (expr instanceof SQLIdentifierExpr) {
            if (SQLUtils.nameEquals(((SQLIdentifierExpr) expr).getName(), column)) {
                return true;
            }
        }
    }
    return false;
}
 

import com.alibaba.druid.sql.SQLUtils; //导入依赖的package包/类
public void simplify() {
    super.simplify();

    for (SQLSelectOrderByItem item : columns) {
        SQLExpr column = item.getExpr();
        if (column instanceof SQLIdentifierExpr) {
            SQLIdentifierExpr identExpr = (SQLIdentifierExpr) column;
            String columnName = identExpr.getName();
            String normalized = SQLUtils.normalize(columnName, dbType);
            if (normalized != columnName) {
                item.setExpr(new SQLIdentifierExpr(columnName));
            }
        }
    }
}