diff --git a/src/explanation/entity-integrity.md b/src/explanation/entity-integrity.md index ba804907..b400dd06 100644 --- a/src/explanation/entity-integrity.md +++ b/src/explanation/entity-integrity.md @@ -213,7 +213,8 @@ in a single statement. ## Schema dimensions -A **dimension** is an independent axis of variation in the data. The rule: +A **schema dimension** — often shortened to *dimension* — is an independent axis of +variation in the data. The rule: > **Any table that introduces a new primary-key attribute introduces a new > dimension.** diff --git a/src/how-to/read-diagrams.ipynb b/src/how-to/read-diagrams.ipynb index d668df94..7c0355f6 100644 --- a/src/how-to/read-diagrams.ipynb +++ b/src/how-to/read-diagrams.ipynb @@ -389,20 +389,7 @@ "cell_type": "markdown", "id": "cell-dim-md", "metadata": {}, - "source": [ - "## Dimensions and Underlined Names\n", - "\n", - "A **dimension** is a new entity type introduced by a table that defines new primary key attributes. Each underlined table introduces exactly **one** dimension—even if it has multiple new PK attributes, together they identify one new entity type.\n", - "\n", - "| Visual | Meaning |\n", - "|--------|--------|\n", - "| **Underlined** | Introduces a new dimension (new entity type) |\n", - "| Not underlined | Exists in the space defined by dimensions from referenced tables |\n", - "\n", - "**Key rules:**\n", - "- Computed tables **never** introduce dimensions (always non-underlined)\n", - "- Part tables **can** introduce dimensions (may be underlined)" - ] + "source": "## Dimensions and Underlined Names\n\nA **schema dimension** (often shortened to *dimension*) is a new entity type introduced by a table that defines new primary key attributes. Each underlined table introduces exactly **one** dimension—even if it has multiple new PK attributes, together they identify one new entity type.\n\n| Visual | Meaning |\n|--------|--------|\n| **Underlined** | Introduces a new dimension (new entity type) |\n| Not underlined | Exists in the space defined by dimensions from referenced tables |\n\n**Key rules:**\n- Computed tables **never** introduce dimensions (always non-underlined)\n- Part tables **can** introduce dimensions (may be underlined)" }, { "cell_type": "code", @@ -3473,4 +3460,4 @@ }, "nbformat": 4, "nbformat_minor": 5 -} +} \ No newline at end of file