suneido.database.query.Update.java Source code

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Here is the source code for suneido.database.query.Update.java

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/* Copyright 2008 (c) Suneido Software Corp. All rights reserved.
 * Licensed under GPLv2.
 */

package suneido.database.query;

import java.util.List;
import java.util.Set;

import com.google.common.collect.ImmutableSet;

import suneido.SuException;
import suneido.SuRecord;
import suneido.database.immudb.Record;
import suneido.database.immudb.Transaction;
import suneido.database.query.expr.Expr;

public class Update extends QueryAction {
    private final Transaction tran;
    private final List<String> fields;
    private final List<Expr> exprs;

    public Update(Transaction tran, Query source, List<String> fields, List<Expr> exprs) {
        super(source);
        this.tran = tran;
        this.fields = fields;
        this.exprs = exprs;
    }

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append("UPDATE ").append(source).append(" SET ");
        for (int i = 0; i < fields.size(); ++i)
            sb.append(fields.get(i)).append("=").append(exprs.get(i)).append(", ");
        return sb.substring(0, sb.length() - 2);
    }

    @Override
    public int execute() {
        Query q = source.transform();
        Set<String> cols = ImmutableSet.copyOf(q.columns());
        List<String> bestKey = q.key_index(cols);
        if (q.optimize(bestKey, cols, noNeeds, false, true) >= IMPOSSIBLE)
            throw new SuException("invalid query");
        q = q.addindex(tran);
        // cSuneido uses source.key_index
        // but this causes problems - maybe need transform first?
        //      List<String> bestKey = source.keys().get(0);
        //      Query q = source.setup();
        if (!q.updateable())
            throw new SuException("update: query not updateable");
        Header hdr = q.header();
        Row row;
        int n = 0;
        Record prevKey = null;
        while (null != (row = q.get(Dir.NEXT))) {
            Record key = row.project(hdr, bestKey);
            // avoid getting stuck on the same key
            // should maybe be in Btree Iter
            if (key.equals(prevKey))
                continue;
            prevKey = key;
            SuRecord surec = row.surec(hdr);
            for (int i = 0; i < fields.size(); ++i)
                surec.put(fields.get(i), exprs.get(i).eval(hdr, row));
            Record newrec = surec.toDbRecord(hdr);
            tran.updateRecord(q.tblnum(), row.firstData(), newrec);
            ++n;
        }
        return n;
    }

}