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diff --git a/SQLiteStudio3/coreSQLiteStudio/impl/dbattacherimpl.h b/SQLiteStudio3/coreSQLiteStudio/impl/dbattacherimpl.h
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+++ b/SQLiteStudio3/coreSQLiteStudio/impl/dbattacherimpl.h
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+#ifndef DBATTACHERIMPL_H
+#define DBATTACHERIMPL_H
+
+#include "dbattacher.h"
+
+class DbAttacherImpl : public DbAttacher
+{
+    public:
+        /**
+         * @brief Creates attacher with the given database as the main.
+         * @param db Database that the query will be executed on.
+         */
+        DbAttacherImpl(Db* db);
+
+        bool attachDatabases(const QString& query);
+        bool attachDatabases(const QList<SqliteQueryPtr>& queries);
+        bool attachDatabases(SqliteQueryPtr query);
+        void detachDatabases();
+        BiStrHash getDbNameToAttach() const;
+        QString getQuery() const;
+
+    private:
+        /**
+         * @brief Does the actual job, after having all input queries as parsed objects.
+         * @return true on success, false on failure.
+         */
+        bool attachDatabases();
+
+        /**
+         * @brief Finds tokens representing databases in the query.
+         * @return List of tokens. Some tokens have non-printable value (spaces, etc), others are database names.
+         */
+        TokenList getDbTokens();
+
+        /**
+         * @brief Detaches all databases currently attached by the attacher.
+         *
+         * Also clears names mappings.
+         */
+        void detachAttached();
+
+        /**
+         * @brief Generates mapping of database name to its Db object for all registered databases.
+         */
+        void prepareNameToDbMap();
+
+        /**
+         * @brief Groups tokens by the name of database they refer to.
+         * @param dbTokens Tokens representing databases in the query.
+         *
+         * This method is used to learn if some database is used more than once in the query,
+         * so we attach it only once, then replace all tokens referring to it by the attach name.
+         */
+        QHash<QString,TokenList> groupDbTokens(const TokenList& dbTokens);
+
+        /**
+         * @brief Tries to attach all required databases.
+         * @param groupedDbTokens Database tokens grouped by database name, as returned from groupDbTokens().
+         * @return true on success, false on any problem.
+         *
+         * Major problem that can happen is when "<tt>ATTACH 'path to file'</tt>" fails for any reason. In that case
+         * detachAttached() is called and false is returned.
+         */
+        bool attachAllDbs(const QHash<QString,TokenList>& groupedDbTokens);
+
+        /**
+         * @brief Creates token-to-token replace map to update the query.
+         * @param dbTokens Tokens representing databases in the query.
+         * @return Mapping to be used when replacing tokens in the query.
+         */
+        QHash<TokenPtr, TokenPtr> getTokenMapping(const TokenList& dbTokens);
+
+        /**
+         * @brief Replaces tokens in the query.
+         * @param tokenMapping Map of tokens to replace.
+         *
+         * Replacing takes place in token lists of each query in the queries member.
+         */
+        void replaceTokensInQueries(const QHash<TokenPtr, TokenPtr>& tokenMapping);
+
+        QList<SqliteQueryPtr> queries;
+        Db* db = nullptr;
+        Dialect dialect;
+        BiStrHash dbNameToAttach;
+        StrHash<Db*> nameToDbMap;
+};
+
+class DbAttacherDefaultFactory : public DbAttacherFactory
+{
+    public:
+        DbAttacher* create(Db* db);
+};
+
+#endif // DBATTACHERIMPL_H