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Storage (Magic xpa 4.x)
The following properties appear in the Storage section:
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Character Set
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Lets you select between ANSI and OEM character sets.
If you are using an Alpha field in an SQL database, then you can select from ANSI or OEM character sets.
The default Char. Set for an XML data source is defined according to the data source.
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Default Storage
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Lets you set table columns to be automatically mapped to the expected storage of the underlying DBMS according to the column’s attribute and the DBMS gateway in use. This ability adds to the transparency of DBMS portability.
If set to Yes, the column will be mapped according to its default mapping, which is determined by the DBMS gateway in use.
If you select the Yes value, the following field properties are disabled: Stored, Size, and Definition.
If set to No, the column will be mapped according to the column’s Storage property.
The Default Storage property is also available for Virtual variables used in Direct SQL tasks.
The default value is No.
See also How Do I Set Data Source Mappings to Support Working with Multiple DBMSs?
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Stored As
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Lets you store data, such as a String, LString, or String Memo.
Zoom from this property to the Storage Type list, which is a list of available storage types.
Every attribute in Magic xpa has several storage types. If not otherwise specified, the SQL gateway uses the most appropriate default mapping to the underlying RDBMS data type.
For example, the Alpha attribute may be stored as a Zstring in Magic xpa. This storage is internal to Magic xpa only. When switching from one RDBMS to another, Magic xpa attempts to maintain the same storage type. For compatibility reasons, however, the storage type may differ from one RDBMS to another. Do not change the Magic xpa default storage types.
Magic xpa's Unicode support means that you can also store Unicode or ZUnicode data. ZUnicode is a null-terminated Unicode string.
For a BLOB column, the Stored As property has the following options: Binary Large Object, Ansi Blob, and Unicode Blob. When you modify the Content property, the Stored As property will automatically be modified.
Note: If you change the underlying database, Magic xpa resets the storage type of every field of the data source according to the new database.
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Modifiable
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Lets you modify the column after it has been created.
If, in an Online task, you move the insertion point to a column specified as Modifiable No and try entering data there, Magic xpa will not accept the new entry.
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Size
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Lets you set the database parameter size. This is available in the column properties.
The column size is limited by the database. For example: MS-SQL, DB2, ODBC, and Memory: 32767, Btrieve: 8000, Oracle: 32511.
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Definition
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You can select Normal or String from the Definition box to define the Database property. This is available in the column properties.
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The Stored as, Size, and Definition properties reflect the Storage Type that describes the internal representation of the column. Magic xpa assigns a default Storage Type and Size, which depend on the column attribute, its picture, and the database used. Ordinarily you will accept the default values assigned by Magic xpa to these properties. When you want to access files created by non-Magic xpa applications, you may have to adjust these properties.
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Defining a lower value for the Size property than for the Picture property is not recommended. Magic xpa will not save a Size value lower than a Picture value after importing or migrating an application or data source. If you want to maintain the difference, you will have to change the value manually.
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Update Style
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Magic xpa lets you make differential updates for tasks that have a Numeric field type, normal storage type and relate to an SQL table. Differential updates can be made for tasks that run in Deferred mode, Nested Deferred mode, or a Within Active Trans mode task that evaluates to deferred in runtime.
This property does not apply to ISAM files.
The Update Style property appears in the Column Properties sheet of the Data repository. The values for the property are:
Absolute – a fixed value (FLD1=X).
Differential – differential values. You can update FLD1 by using the value FLD1+X (FLD1=FLD1+X). See also Differential Update.
A similar property appears in the Column Properties sheet of the Data View Editor. The Actual Update Style property has the same values as the Update Style property and also has an As Table option, which takes the update style from the Update Style property.
See also How Can I Determine Magic xpa Behavior When Several Users Are Modifying the Same Row?
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