Prepare Your Data

When you connect your database to GoodData, the schema of your database is then used inside a workspace to automatically generate a the logical data model (LDM). The LDM is what ultimately determines your analytical options when you build visualizations and dashboards.

To ensure the LDM is generated successfuly, we recommend you consider:

• Supported Data Types
• Recommended Naming Conventions
• How Is LDM Derived

Supported Data Types

Make sure that the columns that you want to include in the model have the supported data types assigned. The data types are validated using the JDBC data types. To find out how the JDBC data types are mapped to the data types in your database, refer to documentation for your specific database.

GoodData supports the following JDBC data types:

Columns with an unsupported data type (for example, when the UUID database data type is mapped to the OTHER JDBC data type) are skipped and not included in the LDM.

Recommended Naming Conventions

We recommend you name the columns in your tables a certain way by adding a specific prefix to each column name. Columns with these prefixes will be automatically converted to a specific type of field when a dataset is created:

The prefixes are not case-sensitive.

If these prefixes are absent, your columns will be mapped using the default configuration. You can always re-map your fields (columns) manually by going to the View details → Data mapping tab for each one of the datasets.

Separators

In the table above, a double underscore (__) is used as a separator between prefixes and entity names, or between separate sections of reference names and label names. Note that in an API request for generating the LDM you can define any string as a separator.

We recommend that the string you want to use as a separator be as unique as possible. Consider the situation when you use an underscore (_) as a separator and you have a column named referencePrefix_table_1_fk_column. This column name cannot be split into three sections as it would be required (prefix, referencedTable, referencedColumn).

Naming Conventions vs. Referential Integrity

Do not apply the naming conventions to the columns that are used as or are included in a primary key or a foreign key in your database. Such columns will be interpreted as grains and references based on referential integrity (see Default Configuration).

How Is LDM Derived

When a declarative definition of the LDM is generated, certain rules are applied that affect how LDM entities are created based on the database. Understanding these rules will help you adjust your database and make the process of generating the LDM smoother and more accurate.

Default Configuration

By default, entities for the LDM are derived from the database based on data types assigned to table columns and referential integrity in the database.

The default configuration has the following limitations:

• It always reads the whole database; you cannot select just a part of the database to read.
• It cannot detect advanced LDM entities such as attribute labels.
• It cannot generate facts from columns with the INT data type.
• It cannot generate grains and references if referential integrity is not maintained in the database.
• It cannot generate proper LDM entities (such as facts, labels, and so on) from columns with incorrectly defined data types.

To overcome these limitations, use the naming conventions in your database to make sure that entities are identified and interpreted correctly regardless of the column data types and referential integrity.

Entity Names in the Generated LDM

In the generated LDM, entity names and descriptions are generated based on the corresponding column names. To make an entity name more human-readable, the following happens when the entity name is injected into the LDM:

• The prefix is removed from the name.
• The first character is upper-cased.
• Any non-alphanumeric character is replaced by a space.