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DDML, a language based on XML (Extensible Markup Language), allows you to logically define the entities you want to add to the Precise schema, such as tables, views, indexes, foreign keys, and all other required components. It covers the common entities available in most popular DBMSs.

After you have defined all database entities in DDML, you must run the DDML creation script to physically create the entities in the database.

General DDML document format

The general format of a DDML document looks as follows:

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Root element of a DDML document. Its children are the main database entities:

<table-definition>, <ddl-definition>, and <view-definition>. The <tables-definition> tag includes the product attribute, which indicates the product of this specific DDML definition.

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<tables-definition> tag

Root element of the DDML document.

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Required. Holds the product short name (product shortcut) consisting if two characters that define the product.

In this case, three custom-defined products are available:

• C1 For customer-defined 1
• C2 For customer-defined 2
• C3 For customer-defined 3

<table-definition> tag

Holds all of the information included in a single table.

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Required. Specifies the table type and can hold one of the following values:

• Statistics. A PMDB table that holds information about certain database activity, summarized into hours or time slices.
• Events. A PMDB table that keeps a log of database incidents.

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Optional. Affects only Oracle and is developed as PCTFREE pctfree .

Can have a value between 0 and 99.

If the PMDB is a Microsoft SQL Server database, this attribute is transformed to fill factor.

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Optional. Affects only Oracle and is developed as STORAGE(oracle-storage-clause). For example:

oracle-storage-clause="initial 1M next 1M minextents 1maxextents unlimited pctincrease 100"

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The <table-definition> tag can have the following children:

• <column-definition>
• <index-definition>
• <foreign-key-definition>

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Optional. Instructs to define an hour-level summary table for this table. Used for time slice statistics tables.

The name of the summary table is specified by the name attribute (required). The summary table name should follow the naming conventions specified in Naming conventions.

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Optional. Instructs to define a day-level summary table for this table.

The name of the summary table is specified by the name attribute (required). The summary table name should follow the naming conventions specified in Naming conventions.

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Optional. Instructs to define a week-level summary table for this table.

The name of the summary table is specified by the name attribute (required). The summary table name should follow the naming conventions specified in Naming conventions.

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Optional. Instructs to define a month-level summary table for this table.

The name of the summary table is specified by the name attribute (required). The summary table name should follow the naming conventions specified in Naming conventions.

<ddl-definition> tag

Holds DDL (Data Definition Language) and DML (Data Manipulation Language) statements that can be performed during installation or uninstallation, such as stored procedures.

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Optional. the RDBMS type on which the DDL generates. Must be one of the following:

• oracle
• mssql
• ""

If left empty (""), the DDL is created on all relational database management systems (RDBMS).

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Optional. The RDBMS version on which the DDL generates. Should have the format 8.1. ... If left empty, the DDL is created on all RDBMS versions.

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Optional. The RDBMS version on which the DDL generates. Must be one of the following:

• INSTALL  Default. During the installation process only.
• UNINSTALL During the uninstallation process only.
• PREINSTALL Before the installation process.
• PREUNINSTALL Before the uninstallation process.

<view-definition> tag

Holds all the parameters required for a view definition.

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Required. Specifies the view type and can hold one of the following values:

• STATISTICS A PMDB view that holds information about certain database activity, summarized into hours or time slices.
• INTERNAL A PMDB view that keeps any other, non-statistical information.

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<column-definition> tag

Holds all the parameters of a column.

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Required. Holds the data type of a column:

• BOOLEAN Does not require data-length or data-scale attributes. These attributes should not be specified. Implementation on all DBMSs:
  • CHAR(1) where T is the boolean TRUE value and F is FALSE.
• CHAR Requires data-length attribute. Implementation on all DBMSs:
  • CHAR(data-length)
• CLOB Requires data-length attribute. Implementation:
  • TEXT for Microsoft SQL Server
  • CLOB for Oracle
• DECIMAL Requires data-length (used for precision) and data-scale attributes. Implementation:
  • NUMBER(data-length, data-scale) for Microsoft SQL Server and IBM UDB Oracle
• FLOAT Requires data-length attribute. Implementation:
  • FLOAT(data-length) for Microsoft SQL Server
  • NUMBER without any parameters for Oracle
• INTEGER Requires data-length attribute. Implementation:
  • data-length less than three: TINYINT; data-length two-to-four: SMALLINT; data-length more than four: BIGINT for Microsoft SQL Server
  • NUMBER(data-length) for Oracle
• TIMESTAMP Does not require data-length or data-scale attributes. These attributes should not be specified. Implementation:
  • DATETIME for Microsoft SQL Server
  • TIME for Oracle
• UNIQUE INTEGER Does not require data-length or data-scale attributes. These attributes should not be specified. This is a data type for a unique integer whose values are generated automatically. Implementation:
  • IDENTITY for Microsoft SQL Server
  • NUMBER(20,0) for Oracle. In addition, a SEQUENCE and a TRIGGER BEFORE INSERT are created, which select the NEXTVAL of the SEQUENCE from DUAL.
• VARCHAR Requires the data-length attribute. Implementation:
  • VARCHAR(data-length) for Microsoft SQL Server
  • VARCHAR2(data-length) for Oracle
• VARBINARY Requires the data-length attribute. Implementation:
  • VARBINARY(data-length) for Microsoft SQL Server
  • RAW(data-length) for Oracle

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Required only for the data types listed below. Specifies the column data length:

• CHAR 
• CLOB
• DECIMAL
• FLOAT
• INTEGER 
• VARCHAR
• VARBINARY 

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Optional. Specifies the column default. Can have the following values:

• NULL if the column is nullable (null=TRUE).
• N/A if no default exists. If the attribute is omitted, this is the default.

A constant value that is equal to the column type:

• BOOLEAN TRUE or FALSE
• CHAR A textual constant, such as ABC CLOB; a textual constant, such as ABC DECIMAL; or a decimal point constant, such as 10.3
• FLOAT A floating point constant, such as 12E7
• INTEGER An integer constant, such as 27
• TIMESTAMP One of the following:
  • A timestamp constant of the format yyyy-mm-dd hh:mm:ss.fffffffff, which is jafa.sql.Timestamp’s format, such as 2020-02-20 23:07:35:175000000. Each DBMS displays a slightly different default. Implementation:
    • 2020-02-20 23:07:35:175 for Microsoft SQL Server
    • TO_DATE('2020-02-20 23:07:35') for Oracle
  • The literal string CURRENT TIMESTAMP. Implementation:
    • GETDATE() for Microsoft SQL Server
    • SYSDATE for Oracle
• UNIQUE INTEGER Default value not required and not allowed.
• VARCHAR A textual constant, such as ABC
• VARBINARY A hex string where every two hexadecimal digits represent one byte, such as A07C889F. Each DBMS displays a slightly different default. Implementation:
  • 0xA07C889F for Microsoft SQL Server
  • HEXTORAW('A07C889F') for Oracle

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Required for the column role in columns of statistics tables. Can have the following values:

• IDENTIFIER A column identifying the sampled entity. The concatenation of all identifiers should uniquely identify the entity.
• DATE A column identifying the sampled period. Its type should be TIMESTAMP and be equal to the beginning of the sampled period.
• SUM A statistics column whose transfer to a higher summary level (such as hourly to daily) should be applied by the SUM function.
• MIN A statistics column whose transfer to a higher summary level (such as hourly to daily) should be applied by the MIN function.
• MAX A statistics column whose transfer to a higher summary level (such as hourly to daily) should be applied by the MAX function.
• AVG A statistics column whose transfer to a higher summary level (such as hourly to daily) should be applied by the AVG function.

Columns required for statistics tables

If the table is a statistics table, you must include the following columns:

• <column-definition name="<table shortcut>_TIMESTAMP" data-type="TIMESTAMP" null="FALSE" type="DATE"/>
• <column-definition name="<table shortcut>_MINUTES_COUNT_SUM" data-type="INTEGER" data-length="9" null="FALSE" type="SUM" default="1"/>
• <column-definition name="<table shortcut>_PWHG_ID" data-type="INTEGER" data-length="4" null="FALSE" type="IDENTIFIER"/>
• <column-definition name="<table shortcut>_PWII_INSTANCE_ID" data-type="INTEGER" data-length="9" null="FALSE" type="IDENTIFIER"/>
• <column-definition name="<table shortcut>_RECIEVED_TIMESTAMP" data-type="TIMESTAMP" null="FALSE" default="CURRENT TIMESTAMP" type="DATE"/>

<index-definition> tag

Holds all the parameters for an index definition.

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Required. Has the value TRUE if this is a primary index and FALSE if it is not. Implementation:

• ALTER TABLE ADD CONSTRAINT for Microsoft SQL Server. Adding a primary constraint in Microsoft SQL Server always results in creating a unique index to enforce the constraint.
• An index is created using the CREATE INDEX statement for Oracle. Then an ALTER TABLE ADD CONSTRAINT is performed to add the primary constraint. The ALTER TABLE ADD CONSTRAINT is suffixed with the USING INDEX clause to instruct Oracle to use the already created index to enforce the constraint and not to create a new one.

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Optional. Has the value TRUE if this is a clustered index and FALSE if it is not. The default is FALSE . A clustered index is an index that physically orders and organizes the table. Implementation:

• CLUSTERED clause for a clustered index, NON CLUSTERED clause for a non-clustered index in Microsoft SQL Server.
• In Oracle, this feature is not used frequently; it requires a complete entity to handle clustering.

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<foreign-key-definition> tag

Holds all the parameters for a foreign-key definition.

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Required. Determines what action is taken if one or more rows in the referencing table point to a row in the referenced table that has been deleted. Can have the following values:

• CASCADE All rows pointing to the deleted row are also deleted. Implementation on all DBMSs: ON DELETE CASCADE
• NO ACTION The deletion fails. Implementation:
  • ON DELETE NO ACTION for Microsoft SQL Server
  • No ON DELETE clause is specified for Oracle. This is the default.

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Required. Determines what action is taken if one or more rows in the referencing table point to a row in the referenced table that has been updated. Can have the following values:

• CASCADE All rows pointing to the deleted row are also deleted. Implementation on all DBMSs: ON UPDATE CASCADE
• NO ACTION The update fails. Implementation:
  • ON UPDATE NO ACTION for Microsoft SQL Server
  • No ON UPDATE clause is specified for Oracle. This is the default.

How to create DDML Documents