Default Values

Explicit NULL is a Value

Explicit NULL does not invoke the default in this toy rule.

highlighted = computed this step

Explicit NULL is a value

Under this toy rule, explicit NULL does not ask for the default.

NULL stays NULL\text{NULL stays NULL}

Supply NULL note

The candidate has 1 explicit NULL, and explicitNullInvokesDefault is no_toy_rule.

explicit NULLs=1\text{explicit NULLs}=1

DEFAULT examples are tiny finite insert checks; SQL dialect completeness, generated defaults, identity columns, triggers, constraints beyond visible NOT NULL, indexes, transactions, performance, and product behavior are out of scope.

Explicit NULL is a value: base rowsidnamestatusnotescore1Adaactiveseed102BennewNULL0 Schema defaultscolumnnotNulldefaultidyesNO_DEFAULTnameyesNO_DEFAULTstatusyesnewnotenononescoreyes0 Candidate resolutioncolumnsupplieddefaultresultsourcestatusreasonidyesNO_DEFAULT3explicitokoknameyesNO_DEFAULTCyexplicitokokstatusnonewnewdefaultokoknoteyesnoneNULLexplicit_NULLokokscoreno00defaultokok Candidate checkfieldvaluedecisionacceptedresolvedRow(3, Cy, new, NULL, 0)reasons()insertedRowIndex2 Rows after candidateidnamestatusnotescore1Adaactiveseed102BennewNULL03CynewNULL0 DEFAULT factsfactvaluebaseRowCount2schemaColumnCount5defaultColumnCount3suppliedColumnCount3omittedColumnCount2appliedDefaultCount2explicitValueCount3explicitNullCount1rejectedReasonCount0candidateDecisionacceptedfinalRowCount3explicitNullInvokesDefaultno_toy_rule

Read the note cell

The note result is NULL even though the schema has a note default.

explicit NULL visible\text{explicit NULL visible}

Summary

Omitted and explicit NULL are different cases here.

omitted≠NULL\text{omitted} \ne \text{NULL}