Tables: @Structure, @Fields, @Indexes

A table .warp file describes a DDS physical file: its columns and its keyed access paths. It’s referenced from a Program/Screen via @References/Tables.

1. Minimal file

@Properties {
    Type : "Table"
}
@Structure {
    Name        : "GRIDDEMO"
    Description : "Sample customers"
    @Fields {
        CustCode char(6)   Description("Customer code")
        Name     char(20)  Description("Name")
        City     char(15)  Description("City")
    }
    @Indexes {
        PrimaryKey ( GRIDDEMOPK, [CustCode] )
        Index ( GRIDDMNOM, [Name] )
    }
}

@Fields: one Name type(...) line per column. Only char/number/date — see Data types. Available modifiers: Description(...), Default(...), AllowNull.
@Indexes: PrimaryKey (required, its fields can’t be AllowNull), Unique, Index — each one as Kind(Name, [Field, ...], "optional description").

2. Referencing it from a Program

@References {
    Tables = ["../tables/TLGRIDDEMO.warp"]
}

The path is relative to the file that references it. Once referenced, its fields become available as bare identifiers inside a For Each/New (see below), and as field(FieldName) in @Variables to inherit its type.

3. Reading rows: For Each In

@Source {
    For Each In GRIDDEMO Index GRIDDMNOM
    Where CustCode = &VCustCode
        &VName = Name
        &VCity = City
    When None
        Message("Customer not found", Error)
    EndFor
}

Index picks the access path (defaults to the sequential-access one if omitted); Where filters by equality; When None runs if no row was found.

4. Inserting rows: New

@Source {
    New In GRIDDEMO
        CustCode = &VCustCode
        Name     = &VName
        City     = &VCity
    When Duplicate
        Message("That code already exists", Error)
    EndNew
}

When Duplicate runs if the insert collides with an existing unique key.

5. Extended documentation

A table can also carry @Documentation (nested inside @Structure, unlike a Program where it goes at the top level) with @Author, @Application, @Module, @Repository and @History (@Creation + @Change per changelog entry) — see @Structure, @Fields, @Indexes for the full detail of each sub-section.

6. Reverse engineering from an existing DDS

If the table already exists on the IBM i, there’s no need to write it by hand: the WaRPGate: Reverse Engineer command in the VSCode extension connects to the IBM i, reads the DDS (and optionally its associated LFs as @Indexes) and generates the corresponding .warp file.

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