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jvx:reference [2020/06/15 08:55] cduncan [DataBooks] |
jvx:reference [2020/06/15 09:10] cduncan [Application Basics] |
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| columnDefinition.setNullable(false); | columnDefinition.setNullable(false); | ||
| </code> | </code> | ||
| - | ==== MetaData ==== | + | ==== Meta Data ==== |
| Most of the column definition is additional information about the column, like if it is nullable, the label of the column, default values, allowed values, and similar information. | Most of the column definition is additional information about the column, like if it is nullable, the label of the column, default values, allowed values, and similar information. | ||
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| ===== Usage Example ===== | ===== Usage Example ===== | ||
| - | Here is a simple example of a ''%%MemDataBook%%'', an ''%%IDataBook%%'' implementation which only operates in memory: | + | Here is a simple example of a ''%%MemDataBook%%'', an ''%%IDataBook%%'' implementation that only operates in memory: |
| <code java> | <code java> | ||
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| * Binary Data | * Binary Data | ||
| - | Text and binary data are both objects (arrays of primitives are objects after all) and numbers are either primitives or objects. Most of the time, if we deal with numbers inside a database, we want them to be of arbitrary precision, which means we must represent them as ''%%BigDecimal%%''. Supporting ''%%double%%'' or ''%%float%%'' in these cases would be dangerous because one might write a ''%%float%%'' into the database [[https://en.wikipedia.org/wiki/Floating-point_arithmetic|which might or might not end up with the correct value]] in the database. To completely eliminate such problems, we only support objects, which means that one is “limited” to the usage of number extensions like ''%%BigLong%%'' and ''%%BigDecimal%%'', which do not suffer from such problems. | + | Text and binary data are both objects (arrays of primitives are objects after all) and numbers are either primitives or objects. Most of the time, if we deal with numbers inside a database, we want them to be of arbitrary precision, which means we must represent them as ''%%BigDecimal%%''. Supporting ''%%double%%'' or ''%%float%%'' in these cases would be dangerous because one might write a ''%%float%%'' into the database [[https://en.wikipedia.org/wiki/Floating-point_arithmetic|, which might or might not end up with the correct value]] in the database. To completely eliminate such problems, we only support objects, which means that one is “limited” to the usage of number extensions like ''%%BigLong%%'' and ''%%BigDecimal%%'', which do not suffer from such problems. |
| ==== Where Are the Data Pages? ==== | ==== Where Are the Data Pages? ==== | ||
| Line 786: | Line 786: | ||
| ====== Application Basics ====== | ====== Application Basics ====== | ||
| - | Let’s talk about the basics, how a [[https://sourceforge.net/projects/jvx/|JVx]] application starts, works and how the connection strings together the client and server side. | + | Let’s talk about the basics: how a [[https://sourceforge.net/projects/jvx/|JVx]] application starts, how it works, and how the connection strings together the client and server side. |
| ===== Multitier Architecture ===== | ===== Multitier Architecture ===== | ||