Anyone that has a partial XSD that describes the M

Question

I know that you cannot fully describe the XML that the TClientDataSet with an XSD schema, as the ROW elements have attributes that have names that vary with the contents.

However, the METADATA section of such an XML should be.

So: is there anyone having a (partial) XSD that describes the METADATA portion of the XML that can be saved with Delphi TClientDataSets?

Regards.

PS:

Thanks for the pointers to XML->XSD conversion tools/sites; I should have written that I did that myself as well, but that generating that XSD in a proper way (i.e. one that covers all possibilities) will need input XML that cover all possibilities (like roundtrip, rowstate, etc). I'll try to come up with a decent XSD that way and post it here.

Answer 1

Edit:
Split the XSD in two parts, and made it more complete by using these files in Delphi XE: dsconst.h, dspickle.h, dsxml.h.
Please PM or comment if you have additions.

The XSD files below seems to work reasonably so far; if you have TClientDataSet XML that does not validate with this, please email me your XML (Google me or put a comment below for my mail address).

First the file CDS.xsd, which includes the file CDS_METADATA_FIELDS_include.xsd further on.
It defines the basic structure of a TClientDataSet XML document: DATAPACKET, containing METADATA and ROWDATA, where METADATA contains FIELDS and PARAMS, and ROWDATA contains ROW elements:

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
    <xs:include schemaLocation="CDS_METADATA_FIELDS_include.xsd"/>
    <!-- DATAPACKET/datapacket -->
    <xs:element name="DATAPACKET" type="datapacket"/>
    <xs:complexType name="datapacket">
        <xs:sequence>
            <xs:element ref="METADATA"/>
            <xs:element ref="ROWDATA"/>
        </xs:sequence>
        <xs:attribute name="Version" type="xs:NMTOKEN" use="required"/>
    </xs:complexType>
    <!-- METADATA/metadata -->
    <xs:element name="METADATA" type="metadata"/>
    <xs:complexType name="metadata">
        <xs:sequence>
            <xs:element ref="FIELDS"/>
            <xs:element ref="PARAMS"/>
        </xs:sequence>
    </xs:complexType>
    <!-- PARAMS/params -->
    <xs:element name="PARAMS" type="params"/>
    <xs:complexType name="params">
        <xs:attribute name="MD_FIELDLINKS" type="xs:string" use="optional"/>
        <xs:attribute name="DEFAULT_ORDER" type="xs:positiveInteger"/>
        <xs:attribute name="LCID" type="xs:positiveInteger"/>
        <xs:attribute name="CHANGE_LOG" type="xs:string" use="optional"/>
        <xs:attribute name="PRIMARY_KEY" type="xs:positiveInteger" use="optional"/>
    </xs:complexType>
    <!-- ROWDATA/rowdata -->
    <xs:element name="ROWDATA" type="rowdata"/>
    <xs:complexType name="rowdata">
        <xs:sequence>
            <xs:element ref="ROW" minOccurs="0" maxOccurs="unbounded"/>
        </xs:sequence>
    </xs:complexType>
    <!-- ROW/row -->
    <xs:element name="ROW" type="row"/>
    <xs:complexType name="row">
        <xs:sequence>
            <xs:any namespace="##any" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
        </xs:sequence>
        <xs:attribute name="RowState" type="xs:NMTOKEN" use="optional"/>
        <xs:anyAttribute namespace="##any" processContents="lax"/>
    </xs:complexType>
</xs:schema>

Note that ROW elements are very loosely typed, as they will contain attribute names that are dynamically defined.

Then the file CDS_METADATA_FIELDS_include.xsd which contains the underlying meta data used by the FIELDS and PARAMS elements.
It is not yet fully complete, as I haven't found CDS XML files containing the keywords mentioned in the comments below.

<?xml version="1.0" encoding="UTF-8"?>
<!-- include portion of the METADATA FIELDS that CDS uses -->
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <!-- FIELDS/fields -->
  <xs:element name="FIELDS" type="fields"/>
  <xs:complexType name="fields">
    <xs:sequence>
      <xs:element ref="FIELD" maxOccurs="unbounded"/>
    </xs:sequence>
  </xs:complexType>
  <!-- FIELD/field -->
  <xs:element name="FIELD" type="field"/>
  <xs:complexType name="field">
    <xs:sequence>
      <xs:element ref="PARAM" minOccurs="0"/>
      <!-- FIELDS is for nested datasets -->
      <xs:element ref="FIELDS" minOccurs="0" maxOccurs="unbounded"/>
      <!-- PARAMS is for nested datasets -->
      <xs:element name="PARAMS" type="fieldParams" minOccurs="0" maxOccurs="unbounded"/>
    </xs:sequence>
    <!-- fieldname is used when the DBMS allows for non-identifier characters (like spaces) in fieldnames -->
    <xs:attribute name="fieldname" use="optional" type="xs:string"/>
    <xs:attribute name="fieldtype" use="required" type="FIELDTYPE"/>
    <xs:attribute name="SUBTYPE" use="optional" type="subtype"/>
    <!-- DECIMALS is for BCD -->
    <xs:attribute name="DECIMALS" type="xs:positiveInteger" use="optional"/>
    <!-- WIDTH is for Character, BCD, Bytes and Unicode -->
    <xs:attribute name="WIDTH" type="xs:positiveInteger" use="optional"/>
    <xs:attribute name="attrname" type="xs:Name" use="required"/>
<!-- need to incorporate these; probably as attributes as FIELD :
#define szUNIQUE_KEY          "UNIQUE_KEY"
#define szSERVER_COL          "SERVER_COL"
#define szCONSTRAINTS         "CONSTRAINTS"
#define szDATASET_CONTEXT     "DATASET_CONTEXT"
#define szDATASET_DELTA       "DATASET_DELTA"
#define szREADONLY            "READONLY"
#define szBDEDOMX             "BDEDOMAIN_X"
#define szBDERECX             "BDERECORD_X"
#define szBDEDEFX             "BDEDEFAULT_X"
#define szAUTOINCVALUE        "AUTOINCVALUE"
#define szELEMENTS            "ELEMENTS"
#define szTABLENAME           "TABLENAME"
#define szTYPENAME            "TYPENAME"
#define szUPDATEMODE          "UPDATEMODE"
#define szMD_SEMANTICS        "MD_SEMANTICS"
#define szCALCULATED          "CALCULATED"
#define szFIELDNAME          "FIELDNAME"
-->
  </xs:complexType>
  <!-- fieldParams -->
  <xs:complexType name="fieldParams">
    <xs:attribute name="DEFAULT_ORDER" type="xs:positiveInteger"/>
    <xs:attribute name="PRIMARY_KEY" type="xs:positiveInteger"/>
    <xs:attribute name="LCID" type="xs:positiveInteger"/>
  </xs:complexType>
  <!-- FIELDTYPE -->
  <xs:simpleType name="FIELDTYPE">
    <xs:restriction base="xs:Name">
      <!-- observed in real life CDS XML: -->
      <xs:enumeration value="byte"/>
      <!-- from Delphi XE file dsxml.h: -->
      <xs:enumeration value="i1"/>
      <xs:enumeration value="i2"/>
      <xs:enumeration value="i4"/>
      <xs:enumeration value="i8"/>
      <xs:enumeration value="ui1"/>
      <xs:enumeration value="ui2"/>
      <xs:enumeration value="ui4"/>
      <xs:enumeration value="ui8"/>
      <xs:enumeration value="r4"/>
      <xs:enumeration value="r8"/>
      <xs:enumeration value="r10"/>
<!-- szXMLFloat/szXMLNumber <xs:enumeration value="r8"/> -->
      <xs:enumeration value="fixed"/>
      <xs:enumeration value="fixedFMT"/>
      <xs:enumeration value="boolean"/>
      <xs:enumeration value="date"/>
      <xs:enumeration value="dateTime"/>
      <xs:enumeration value="time"/>
      <xs:enumeration value="array"/>
      <xs:enumeration value="struct"/>
      <xs:enumeration value="nested"/>
      <xs:enumeration value="string.uni"/>
      <xs:enumeration value="string"/>
      <xs:enumeration value="bin.hex"/>
      <xs:enumeration value="IntArray"/>
      <xs:enumeration value="UIntArray"/>
      <xs:enumeration value="SQLdateTime"/>
      <xs:enumeration value="SQLdateTimeOffset"/>
    </xs:restriction>
  </xs:simpleType>
  <!-- subtype -->
  <xs:simpleType name="subtype">
    <xs:restriction base="xs:Name">
      <xs:enumeration value="Text"/>
      <xs:enumeration value="Binary"/>
      <xs:enumeration value="Formatted"/>
      <xs:enumeration value="Ole"/>
      <xs:enumeration value="Graphics"/>
      <xs:enumeration value="dBASEOle"/>
      <xs:enumeration value="TypedBinary"/>
      <xs:enumeration value="Money"/>
      <xs:enumeration value="Autoinc"/>
      <xs:enumeration value="AccessOle"/>
      <xs:enumeration value="HMemo"/>
      <xs:enumeration value="HBinary"/>
      <xs:enumeration value="ADTNestedTable"/>
      <xs:enumeration value="FixedChar"/>
      <xs:enumeration value="Reference"/>
      <xs:enumeration value="BFile"/>
      <xs:enumeration value="ADTDate"/>
      <xs:enumeration value="Guid"/>
      <xs:enumeration value="WideText"/>
      <!-- Binary is required for fieldtype="bin.hex" -->
      <!-- FixedChar is required for fieldtype="string" when the field is CHAR (but not NCHAR) -->
      <!-- Guid is required for fieldtype="string" when the field is GUID -->
      <!-- Text is required for fieldtype="bin.hex" when the underlying field is TEXT or NTEXT (memo?) -->
      <!-- Money is required for fieldtype="float" when the underlying field is CURRENCY -->
    </xs:restriction>
  </xs:simpleType>
  <!-- PARAM/param -->
  <xs:element name="PARAM" type="param"/>
  <xs:complexType name="param">
    <xs:attribute name="Name" type="paramName" use="required"/>
    <!-- two forms of Value are possible; xs:Name is for ORIGIN; xs:postiveInteger is for PROVFLAGS (in combination with Type)
        <xs:attribute name="Value" type="xs:Name" use="required"/>
        <xs:attribute name="Value" type="xs:postiveInteger" use="required"/>
-->
    <xs:attribute name="Value" type="xs:string" use="required"/>
    <xs:attribute name="Type" type="FIELDTYPE" use="optional"/>
    <xs:attribute name="Roundtrip" type="xs:Name" use="required" fixed="True"/>
  </xs:complexType>
  <!-- paramName -->
  <xs:simpleType name="paramName">
    <xs:restriction base="xs:Name">
      <xs:enumeration value="ORIGIN"/>
      <xs:enumeration value="PROVFLAGS"/>
    </xs:restriction>
  </xs:simpleType>
</xs:schema>

Regards.

Answer 2

Well I couldn't find one either, so I used this website to generate this schema based on a ClientDataSet XML file.

<?xml version="1.0" encoding="UTF-8" ?>

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="DATAPACKET">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="METADATA" />
        <xs:element ref="ROWDATA" />
      </xs:sequence>
      <xs:attribute name="Version" type="xs:NMTOKEN" use="required" />
    </xs:complexType>
  </xs:element>

  <xs:element name="FIELD">
    <xs:complexType>
      <xs:attribute name="fieldtype" type="xs:NMTOKEN" use="required" />
      <xs:attribute name="WIDTH" type="xs:NMTOKEN" use="optional" />
      <xs:attribute name="attrname" type="xs:NMTOKEN" use="required" />
      <xs:attribute name="required" type="xs:NMTOKEN" use="optional" />
    </xs:complexType>
  </xs:element>

  <xs:element name="FIELDS">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="FIELD" maxOccurs="unbounded" />
      </xs:sequence>
    </xs:complexType>
  </xs:element>

  <xs:element name="METADATA">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="FIELDS" />
        <xs:element ref="PARAMS" />
      </xs:sequence>
    </xs:complexType>
  </xs:element>

  <xs:element name="PARAMS">
    <xs:complexType>
      <xs:attribute name="CHANGE_LOG" type="xs:string" use="required" />
    </xs:complexType>
  </xs:element>

  <xs:element name="ROW">
    <xs:complexType>
    </xs:complexType>
  </xs:element>

  <xs:element name="ROWDATA">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="ROW" maxOccurs="unbounded" />
      </xs:sequence>
    </xs:complexType>
  </xs:element>

</xs:schema>

Answer 3

I am a total newbie in Delphi, but had to deal with parsing a TClientDataSet in XML format. I also needed a list of all the possible values for the field type. Did some digging into the Delphi source and came up with this list.

If you want to include the field types in the schema then you should include all the types listed here:

<xs:enumeration value="string" />
<xs:enumeration value="id" />
<xs:enumeration value="idref" />
<xs:enumeration value="idrefs" />
<xs:enumeration value="entity" />
<xs:enumeration value="entities" />
<xs:enumeration value="nmtoken" />
<xs:enumeration value="nmtokens" />
<xs:enumeration value="number" />
<xs:enumeration value="int" />
<xs:enumeration value="enumeration" />
<xs:enumeration value="notation" />
<xs:enumeration value="fixed" />
<xs:enumeration value="boolean" />
<xs:enumeration value="dateTime" />
<xs:enumeration value="dateTime.tz" />
<xs:enumeration value="date" />
<xs:enumeration value="time" />
<xs:enumeration value="time.tz" />
<xs:enumeration value="i1" />
<xs:enumeration value="byte" />
<xs:enumeration value="i2" />
<xs:enumeration value="i4" />
<xs:enumeration value="i8" />
<xs:enumeration value="ui1" />
<xs:enumeration value="ui2" />
<xs:enumeration value="ui4" />
<xs:enumeration value="ui8" />
<xs:enumeration value="r4" />
<xs:enumeration value="r8" />
<xs:enumeration value="float" />
<xs:enumeration value="char" />
<xs:enumeration value="uuid" />
<xs:enumeration value="bin.hex" />
<xs:enumeration value="bin.base64" />

Thanks for a doing a nice job of defining this schema. This helps a lot.