public void printHelp()

in paimon-flink/paimon-flink-common/src/main/java/org/apache/paimon/flink/action/MergeIntoActionFactory.java [100:183]

• 76 lines of code
• 1 McCabe index (conditional complexity)

    public void printHelp() {
        System.out.println("Action \"merge-into\" simulates the \"MERGE INTO\" syntax.");
        System.out.println();

        System.out.println("Syntax:");
        System.out.println(
                "  merge-into --warehouse <warehouse-path>\n"
                        + "             --database <database-name>\n"
                        + "             --table <target-table-name>\n"
                        + "             [--target-as <target-table-alias>]\n"
                        + "             [--source-sql <sql> ...]\n"
                        + "             --source-table <source-table-name>\n"
                        + "             --on <merge-condition>\n"
                        + "             --merge-actions <matched-upsert,matched-delete,not-matched-insert,not-matched-by-source-upsert,not-matched-by-source-delete>\n"
                        + "             --matched-upsert-condition <matched-condition>\n"
                        + "             --matched-upsert-set <upsert-changes>\n"
                        + "             --matched-delete-condition <matched-condition>\n"
                        + "             --not-matched-insert-condition <not-matched-condition>\n"
                        + "             --not-matched-insert-values <insert-values>\n"
                        + "             --not-matched-by-source-upsert-condition <not-matched-by-source-condition>\n"
                        + "             --not-matched-by-source-upsert-set <not-matched-upsert-changes>\n"
                        + "             --not-matched-by-source-delete-condition <not-matched-by-source-condition>");

        System.out.println("  matched-upsert-changes format:");
        System.out.println(
                "    col=<source-table>.col | expression [, ...] (do not add '<target-table>.' before 'col')");
        System.out.println(
                "    * (upsert with all source cols; require target table's schema is equal to source's)");

        System.out.println("  not-matched-upsert-changes format:");
        System.out.println("    col=expression (cannot use source table's col)");

        System.out.println("  insert-values format:");
        System.out.println(
                "    col1,col2,...,col_end (must specify values of all columns; can use <source-table>.col or expression)");
        System.out.println(
                "    * (insert with all source cols; require target table's schema is equal to source's)");

        System.out.println(
                "  not-matched-condition: cannot use target table's columns to construct condition expression.");
        System.out.println(
                "  not-matched-by-source-condition: cannot use source table's columns to construct condition expression.");

        System.out.println("  alternative arguments:");
        System.out.println("    --path <table-path> to represent the table path.");
        System.out.println();

        System.out.println("Note: ");
        System.out.println("  1. Target table must has primary keys.");
        System.out.println(
                "  2. All conditions, set changes and values should use Flink SQL syntax. Please quote them with \" to escape special characters.");
        System.out.println(
                "  3. You can pass sqls by --source-sql to config environment and create source table at runtime");
        System.out.println("  4. Target alias cannot be duplicated with existed table name.");
        System.out.println(
                "  5. If the source table is not in the current catalog and current database, "
                        + "the source-table-name must be qualified (database.table or catalog.database.table if in different catalog).");
        System.out.println("  6. At least one merge action must be specified.");
        System.out.println("  7. How to determine the changed rows with different \"matched\":");
        System.out.println(
                "    matched: changed rows are from target table and each can match a source table row "
                        + "based on merge-condition and optional matched-condition.");
        System.out.println(
                "    not-matched: changed rows are from source table and all rows cannot match any target table row "
                        + "based on merge-condition and optional not-matched-condition.");
        System.out.println(
                "    not-matched-by-source: changed rows are from target table and all row cannot match any source table row "
                        + "based on merge-condition and optional not-matched-by-source-condition.");
        System.out.println(
                "  8. If both matched-upsert and matched-delete actions are present, their conditions must both be present too "
                        + "(same to not-matched-by-source-upsert and not-matched-by-source-delete). Otherwise, all conditions are optional.");
        System.out.println();

        System.out.println("Examples:");
        System.out.println(
                "  merge-into --path hdfs:///path/to/T\n"
                        + "             --source-table S\n"
                        + "             --on \"T.k = S.k\"\n"
                        + "             --merge-actions matched-upsert\n"
                        + "             --matched-upsert-condition \"T.v <> S.v\"\n"
                        + "             --matched-upsert-set \"v = S.v\"");
        System.out.println(
                "  It will find matched rows of target table that meet condition (T.k = S.k), then update T.v with S.v where (T.v <> S.v).");
    }