Virtual Properties - On-Demand Calculated Attributes | Tags

<h2 id="virtual-properties" class="position-relative d-flex align-items-center group"> Virtual Properties <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="virtual-properties" aria-haspopup="dialog" aria-label="Share link: Virtual Properties"> Share link </button> </h2><div id="headingShareModal" class="heading-share-modal" role="dialog" aria-modal="true" aria-labelledby="headingShareTitle" hidden> <div class="hsm-dialog" role="document"> <div class="hsm-header"> <h2 id="headingShareTitle" class="h6 mb-0 fw-bold">Share this section</h2> <button type="button" class="hsm-close" aria-label="Close"> </button> </div> <div class="hsm-body"> <label for="headingShareInput" class="form-label small text-muted mb-1 text-uppercase fw-bold" style="font-size: 0.7rem; letter-spacing: 0.5px;">Permalink</label> <div class="input-group mb-4 hsm-url-group"> <input id="headingShareInput" type="text" class="form-control font-monospace" readonly aria-readonly="true" style="font-size: 0.85rem;" /> <button class="btn btn-primary hsm-copy" type="button" aria-label="Copy" title="Copy"> </button> </div> <div class="small fw-bold mb-2 text-muted text-uppercase" style="font-size: 0.7rem; 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They provide dynamically computed values derived from stored properties, relationships, or external data sources without consuming disk space. Ideal for transient calculations, display formatting, and derived data that changes frequently or is rarely queried. <h3 id="understanding-virtual-properties" class="position-relative d-flex align-items-center group"> Understanding Virtual Properties <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="understanding-virtual-properties" aria-haspopup="dialog" aria-label="Share link: Understanding Virtual Properties"> Share link </button> </h3> <h4 id="what-are-virtual-properties" class="position-relative d-flex align-items-center group"> What are Virtual Properties? <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="what-are-virtual-properties" aria-haspopup="dialog" aria-label="Share link: What are Virtual Properties?"> Share link </button> </h4>Virtual properties offer zero-storage computation: Never Stored - Calculated only when accessed, no disk persistence Always Fresh - Reflect current state of underlying data Zero Storage Cost - No disk space or memory overhead Flexible - Easy to modify without data migration Query-Time Evaluation - Computed during SELECT execution <h4 id="virtual-vs-computed-vs-stored-properties" class="position-relative d-flex align-items-center group"> Virtual vs Computed vs Stored Properties <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="virtual-vs-computed-vs-stored-properties" aria-haspopup="dialog" aria-label="Share link: Virtual vs Computed vs Stored Properties"> Share link </button> </h4><table> <thead> <tr> <th>Aspect</th> <th>Stored Property</th> <th>Computed Property</th> <th>Virtual Property</th> </tr> </thead> <tbody> <tr> <td>Storage</td> <td>Full persistence</td> <td>Sometimes cached</td> <td>Never stored</td> </tr> <tr> <td>Calculation</td> <td>Never</td> <td>On write or read</td> <td>Always on read</td> </tr> <tr> <td>Read Performance</td> <td>Fastest</td> <td>Medium</td> <td>Slowest</td> </tr> <tr> <td>Write Performance</td> <td>Fastest</td> <td>Slower (compute)</td> <td>N/A (no writes)</td> </tr> <tr> <td>Data Freshness</td> <td>May be stale</td> <td>Always current</td> <td>Always current</td> </tr> <tr> <td>Disk Usage</td> <td>High</td> <td>Medium</td> <td>Zero</td> </tr> <tr> <td>Indexable</td> <td>Yes</td> <td>Yes</td> <td>No</td> </tr> <tr> <td>Use Case</td> <td>Core data</td> <td>Frequently queried</td> <td>Rarely queried</td> </tr> </tbody> </table> <h4 id="when-to-use-virtual-properties" class="position-relative d-flex align-items-center group"> When to Use Virtual Properties <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="when-to-use-virtual-properties" aria-haspopup="dialog" aria-label="Share link: When to Use Virtual Properties"> Share link </button> </h4>Ideal For: <ul> <li>Display formatting (phone numbers, dates, names)</li> <li>Simple arithmetic transformations</li> <li>Frequently changing business logic</li> <li>Properties queried infrequently</li> <li>Transient derived values</li> <li>Presentation layer logic</li> </ul> Avoid When: <ul> <li>Need to filter/sort by the property frequently</li> <li>Complex expensive computations</li> <li>Aggregations across many nodes</li> <li>Need indexes for performance</li> <li>Value used in WHERE clauses often</li> </ul> <h3 id="defining-virtual-properties" class="position-relative d-flex align-items-center group"> Defining Virtual Properties <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="defining-virtual-properties" aria-haspopup="dialog" aria-label="Share link: Defining Virtual Properties"> Share link </button> </h3> <h4 id="basic-virtual-properties" class="position-relative d-flex align-items-center group"> Basic Virtual Properties <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="basic-virtual-properties" aria-haspopup="dialog" aria-label="Share link: Basic Virtual Properties"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">CREATE PROPERTY TYPE Person ( first_name STRING, last_name STRING, birth_date DATE, email STRING, -- Virtual properties for display VIRTUAL full_name STRING AS ( first_name || ' ' || last_name ), VIRTUAL display_name STRING AS ( CASE WHEN first_name IS NOT NULL AND last_name IS NOT NULL THEN first_name || ' ' || last_name WHEN first_name IS NOT NULL THEN first_name WHEN last_name IS NOT NULL THEN last_name ELSE 'Anonymous' END ), VIRTUAL initials STRING AS ( UPPER(SUBSTRING(first_name, 1, 1) || SUBSTRING(last_name, 1, 1)) ), -- Age calculation (always current) VIRTUAL age INTEGER AS ( DATEDIFF(YEAR, birth_date, CURRENT_DATE) ), VIRTUAL is_adult BOOLEAN AS ( age >= 18 ), -- Email domain extraction VIRTUAL email_domain STRING AS ( SUBSTRING(email FROM POSITION('@' IN email) + 1) ), VIRTUAL email_username STRING AS ( SUBSTRING(email FROM 1 FOR POSITION('@' IN email) - 1) ) ); </code></pre></div> <h4 id="formatting-virtual-properties" class="position-relative d-flex align-items-center group"> Formatting Virtual Properties <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="formatting-virtual-properties" aria-haspopup="dialog" aria-label="Share link: Formatting Virtual Properties"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">CREATE PROPERTY TYPE Contact ( phone STRING, -- Stored as "1234567890" address_line1 STRING, address_line2 STRING, city STRING, state STRING, zip STRING, country STRING, -- Phone number formatting VIRTUAL formatted_phone STRING AS ( CASE WHEN LENGTH(phone) = 10 THEN '(' || SUBSTRING(phone, 1, 3) || ') ' || SUBSTRING(phone, 4, 3) || '-' || SUBSTRING(phone, 7, 4) WHEN LENGTH(phone) = 11 THEN '+' || SUBSTRING(phone, 1, 1) || ' (' || SUBSTRING(phone, 2, 3) || ') ' || SUBSTRING(phone, 5, 3) || '-' || SUBSTRING(phone, 8, 4) ELSE phone END ), -- Full address formatting VIRTUAL full_address STRING AS ( address_line1 || CASE WHEN address_line2 IS NOT NULL THEN ', ' || address_line2 ELSE '' END || ', ' || city || ', ' || state || ' ' || zip || CASE WHEN country IS NOT NULL AND country <> 'USA' THEN ', ' || country ELSE '' END ), -- Short address for display VIRTUAL short_address STRING AS ( city || ', ' || state ) ); </code></pre></div> <h4 id="relationship-based-virtual-properties" class="position-relative d-flex align-items-center group"> Relationship-Based Virtual Properties <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="relationship-based-virtual-properties" aria-haspopup="dialog" aria-label="Share link: Relationship-Based Virtual Properties"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">CREATE PROPERTY TYPE User ( id STRING, name STRING, created_at TIMESTAMP, -- Relationship counts (calculated on access) VIRTUAL follower_count INTEGER AS ( SELECT COUNT(*) FROM MATCH (this)<-[:FOLLOWS]-(follower:User) ), VIRTUAL following_count INTEGER AS ( SELECT COUNT(*) FROM MATCH (this)-[:FOLLOWS]->(following:User) ), VIRTUAL friend_count INTEGER AS ( SELECT COUNT(*) FROM MATCH (this)-[:FRIEND]-(friend:User) ), VIRTUAL post_count INTEGER AS ( SELECT COUNT(*) FROM MATCH (this)-[:POSTED]->(post:Post) ), -- Derived metrics VIRTUAL follower_ratio DECIMAL AS ( CAST(follower_count AS DECIMAL) / NULLIF(following_count, 0) ), VIRTUAL engagement_rate DECIMAL AS ( CAST(follower_count + post_count * 10 AS DECIMAL) / NULLIF(DATEDIFF(DAY, created_at, NOW()), 0) ), -- List properties VIRTUAL follower_ids LIST<STRING> AS ( SELECT u.id FROM MATCH (this)<-[:FOLLOWS]-(u:User) ORDER BY u.name ), VIRTUAL following_ids LIST<STRING> AS ( SELECT u.id FROM MATCH (this)-[:FOLLOWS]->(u:User) ORDER BY u.name ), -- Boolean checks VIRTUAL has_followers BOOLEAN AS (follower_count > 0), VIRTUAL is_following_anyone BOOLEAN AS (following_count > 0), VIRTUAL is_active BOOLEAN AS ( post_count > 0 AND DATEDIFF(DAY, created_at, NOW()) > 30 ) ); </code></pre></div> <h4 id="time-based-virtual-properties" class="position-relative d-flex align-items-center group"> Time-Based Virtual Properties <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="time-based-virtual-properties" aria-haspopup="dialog" aria-label="Share link: Time-Based Virtual Properties"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">CREATE PROPERTY TYPE Order ( id STRING, created_at TIMESTAMP, updated_at TIMESTAMP, shipped_at TIMESTAMP, delivered_at TIMESTAMP, status STRING, total DECIMAL, -- Time since events VIRTUAL days_since_created INTEGER AS ( DATEDIFF(DAY, created_at, NOW()) ), VIRTUAL hours_since_updated INTEGER AS ( DATEDIFF(HOUR, updated_at, NOW()) ), -- Time periods VIRTUAL is_recent BOOLEAN AS (days_since_created <= 7), VIRTUAL is_this_month BOOLEAN AS ( MONTH(created_at) = MONTH(NOW()) AND YEAR(created_at) = YEAR(NOW()) ), -- Processing times VIRTUAL processing_time_hours INTEGER AS ( CASE WHEN shipped_at IS NOT NULL THEN DATEDIFF(HOUR, created_at, shipped_at) ELSE NULL END ), VIRTUAL delivery_time_hours INTEGER AS ( CASE WHEN delivered_at IS NOT NULL AND shipped_at IS NOT NULL THEN DATEDIFF(HOUR, shipped_at, delivered_at) ELSE NULL END ), VIRTUAL total_time_hours INTEGER AS ( CASE WHEN delivered_at IS NOT NULL THEN DATEDIFF(HOUR, created_at, delivered_at) ELSE NULL END ), -- Order age category VIRTUAL age_category STRING AS ( CASE WHEN days_since_created <= 1 THEN 'today' WHEN days_since_created <= 7 THEN 'this_week' WHEN days_since_created <= 30 THEN 'this_month' WHEN days_since_created <= 90 THEN 'recent' WHEN days_since_created <= 365 THEN 'this_year' ELSE 'old' END ), -- Status checks VIRTUAL is_pending BOOLEAN AS (status IN ('pending', 'processing')), VIRTUAL is_completed BOOLEAN AS (status = 'delivered'), VIRTUAL is_overdue BOOLEAN AS ( status IN ('pending', 'processing') AND days_since_created > 7 ), -- Price categorization VIRTUAL price_tier STRING AS ( CASE WHEN total < 25 THEN 'budget' WHEN total < 100 THEN 'standard' WHEN total < 500 THEN 'premium' ELSE 'luxury' END ) ); </code></pre></div> <h3 id="real-world-use-cases" class="position-relative d-flex align-items-center group"> Real-World Use Cases <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="real-world-use-cases" aria-haspopup="dialog" aria-label="Share link: Real-World Use Cases"> Share link </button> </h3> <h4 id="e-commerce-product-display" class="position-relative d-flex align-items-center group"> E-Commerce Product Display <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="e-commerce-product-display" aria-haspopup="dialog" aria-label="Share link: E-Commerce Product Display"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">CREATE PROPERTY TYPE Product ( name STRING, base_price DECIMAL, discount_percentage DECIMAL, cost DECIMAL, stock_quantity INTEGER, category STRING, brand STRING, -- Pricing display VIRTUAL discount_amount DECIMAL AS ( base_price * discount_percentage / 100 ), VIRTUAL sale_price DECIMAL AS ( base_price - discount_amount ), VIRTUAL formatted_price STRING AS ( '$' || CAST(ROUND(sale_price, 2) AS STRING) ), VIRTUAL savings_display STRING AS ( CASE WHEN discount_percentage > 0 THEN 'Save $' || CAST(ROUND(discount_amount, 2) AS STRING) || ' (' || CAST(discount_percentage AS STRING) || '% off)' ELSE NULL END ), -- Stock status VIRTUAL in_stock BOOLEAN AS (stock_quantity > 0), VIRTUAL stock_status STRING AS ( CASE WHEN stock_quantity = 0 THEN 'Out of Stock' WHEN stock_quantity < 5 THEN 'Only ' || CAST(stock_quantity AS STRING) || ' left!' WHEN stock_quantity < 20 THEN 'Low Stock' ELSE 'In Stock' END ), VIRTUAL stock_badge_color STRING AS ( CASE WHEN stock_quantity = 0 THEN 'red' WHEN stock_quantity < 5 THEN 'orange' WHEN stock_quantity < 20 THEN 'yellow' ELSE 'green' END ), -- Profit metrics (for internal use) VIRTUAL profit_per_unit DECIMAL AS (sale_price - cost), VIRTUAL profit_margin_percent DECIMAL AS ( (sale_price - cost) / NULLIF(sale_price, 0) * 100 ), -- Review aggregation VIRTUAL avg_rating DECIMAL AS ( SELECT AVG(r.rating) FROM MATCH (this)<-[:REVIEWS]-(r:Review) ), VIRTUAL review_count INTEGER AS ( SELECT COUNT(*) FROM MATCH (this)<-[:REVIEWS]-(r:Review) ), VIRTUAL rating_display STRING AS ( CASE WHEN review_count = 0 THEN 'No reviews yet' ELSE CAST(ROUND(avg_rating, 1) AS STRING) || '/5 (' || CAST(review_count AS STRING) || ' reviews)' END ), -- SEO-friendly slug VIRTUAL url_slug STRING AS ( LOWER(REPLACE(REPLACE(name, ' ', '-'), '''', '')) ) ); </code></pre></div> <h4 id="user-profile-display" class="position-relative d-flex align-items-center group"> User Profile Display <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="user-profile-display" aria-haspopup="dialog" aria-label="Share link: User Profile Display"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">CREATE PROPERTY TYPE UserProfile ( user_id STRING, username STRING, first_name STRING, last_name STRING, bio TEXT, location STRING, website_url STRING, twitter_handle STRING, joined_date TIMESTAMP, last_active_at TIMESTAMP, profile_image_url STRING, cover_image_url STRING, -- Display name logic VIRTUAL display_name STRING AS ( COALESCE( NULLIF(first_name || ' ' || last_name, ' '), username, 'User' || user_id ) ), -- Membership duration VIRTUAL member_since STRING AS ( CASE WHEN DATEDIFF(DAY, joined_date, NOW()) < 30 THEN 'Joined ' || CAST(DATEDIFF(DAY, joined_date, NOW()) AS STRING) || ' days ago' WHEN DATEDIFF(MONTH, joined_date, NOW()) < 12 THEN 'Member for ' || CAST(DATEDIFF(MONTH, joined_date, NOW()) AS STRING) || ' months' ELSE 'Member for ' || CAST(DATEDIFF(YEAR, joined_date, NOW()) AS STRING) || ' years' END ), -- Activity status VIRTUAL activity_status STRING AS ( CASE WHEN DATEDIFF(MINUTE, last_active_at, NOW()) < 5 THEN 'Online' WHEN DATEDIFF(HOUR, last_active_at, NOW()) < 1 THEN 'Active recently' WHEN DATEDIFF(DAY, last_active_at, NOW()) < 1 THEN 'Active today' WHEN DATEDIFF(DAY, last_active_at, NOW()) < 7 THEN 'Active this week' ELSE 'Inactive' END ), VIRTUAL status_badge_color STRING AS ( CASE WHEN DATEDIFF(MINUTE, last_active_at, NOW()) < 5 THEN 'green' WHEN DATEDIFF(HOUR, last_active_at, NOW()) < 1 THEN 'yellow' ELSE 'gray' END ), -- Social links VIRTUAL twitter_url STRING AS ( CASE WHEN twitter_handle IS NOT NULL THEN 'https://twitter.com/' || twitter_handle ELSE NULL END ), VIRTUAL profile_url STRING AS ( '/users/' || username ), -- Profile completeness VIRTUAL profile_completeness INTEGER AS ( (CASE WHEN first_name IS NOT NULL THEN 10 ELSE 0 END) + (CASE WHEN last_name IS NOT NULL THEN 10 ELSE 0 END) + (CASE WHEN bio IS NOT NULL THEN 20 ELSE 0 END) + (CASE WHEN location IS NOT NULL THEN 10 ELSE 0 END) + (CASE WHEN website_url IS NOT NULL THEN 10 ELSE 0 END) + (CASE WHEN profile_image_url IS NOT NULL THEN 20 ELSE 0 END) + (CASE WHEN cover_image_url IS NOT NULL THEN 20 ELSE 0 END) ), VIRTUAL profile_complete BOOLEAN AS (profile_completeness >= 80), -- Truncated bio for previews VIRTUAL bio_preview STRING AS ( CASE WHEN LENGTH(bio) <= 100 THEN bio ELSE SUBSTRING(bio, 1, 97) || '...' END ) ); </code></pre></div> <h4 id="financial-account-summary" class="position-relative d-flex align-items-center group"> Financial Account Summary <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="financial-account-summary" aria-haspopup="dialog" aria-label="Share link: Financial Account Summary"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">CREATE PROPERTY TYPE Account ( account_number STRING, account_type STRING, balance DECIMAL, currency STRING, interest_rate DECIMAL, opened_date DATE, status STRING, -- Display formatting VIRTUAL masked_account_number STRING AS ( '****' || SUBSTRING(account_number, LENGTH(account_number) - 3, 4) ), VIRTUAL formatted_balance STRING AS ( CASE currency WHEN 'USD' THEN '$' || CAST(ROUND(balance, 2) AS STRING) WHEN 'EUR' THEN '€' || CAST(ROUND(balance, 2) AS STRING) WHEN 'GBP' THEN '£' || CAST(ROUND(balance, 2) AS STRING) ELSE CAST(ROUND(balance, 2) AS STRING) || ' ' || currency END ), -- Account age VIRTUAL account_age_years DECIMAL AS ( DATEDIFF(DAY, opened_date, CURRENT_DATE) / 365.25 ), VIRTUAL account_age_display STRING AS ( CASE WHEN DATEDIFF(DAY, opened_date, CURRENT_DATE) < 30 THEN CAST(DATEDIFF(DAY, opened_date, CURRENT_DATE) AS STRING) || ' days old' WHEN DATEDIFF(MONTH, opened_date, CURRENT_DATE) < 12 THEN CAST(DATEDIFF(MONTH, opened_date, CURRENT_DATE) AS STRING) || ' months old' ELSE CAST(FLOOR(account_age_years) AS STRING) || ' years old' END ), -- Interest calculations VIRTUAL monthly_interest DECIMAL AS ( balance * interest_rate / 12 / 100 ), VIRTUAL annual_interest DECIMAL AS ( balance * interest_rate / 100 ), VIRTUAL interest_display STRING AS ( CAST(interest_rate AS STRING) || '% APY' ), -- Balance status VIRTUAL balance_status STRING AS ( CASE WHEN balance < 0 THEN 'Overdrawn' WHEN balance = 0 THEN 'Zero Balance' WHEN balance < 100 THEN 'Low Balance' WHEN balance < 10000 THEN 'Normal' ELSE 'High Balance' END ), VIRTUAL balance_badge_color STRING AS ( CASE WHEN balance < 0 THEN 'red' WHEN balance < 100 THEN 'orange' ELSE 'green' END ), -- Account status VIRTUAL is_active BOOLEAN AS (status = 'active'), VIRTUAL is_frozen BOOLEAN AS (status = 'frozen'), VIRTUAL status_display STRING AS ( CASE status WHEN 'active' THEN 'Active' WHEN 'frozen' THEN 'Temporarily Frozen' WHEN 'closed' THEN 'Closed' WHEN 'pending' THEN 'Pending Activation' ELSE INITCAP(status) END ) ); </code></pre></div> <h3 id="querying-virtual-properties" class="position-relative d-flex align-items-center group"> Querying Virtual Properties <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="querying-virtual-properties" aria-haspopup="dialog" aria-label="Share link: Querying Virtual Properties"> Share link </button> </h3> <h4 id="selection-and-filtering" class="position-relative d-flex align-items-center group"> Selection and Filtering <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="selection-and-filtering" aria-haspopup="dialog" aria-label="Share link: Selection and Filtering"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Select virtual properties MATCH (p:Person) RETURN p.first_name, p.last_name, p.full_name, -- Virtual property p.age, -- Virtual property p.email_domain; -- Virtual property -- Filter using virtual properties MATCH (p:Person) WHERE p.age >= 21 AND p.is_adult = true RETURN p.display_name, p.age; -- Sort by virtual property MATCH (u:User) RETURN u.name, u.follower_ratio ORDER BY u.follower_ratio DESC LIMIT 10; </code></pre></div> <h4 id="conditional-logic-with-virtual-properties" class="position-relative d-flex align-items-center group"> Conditional Logic with Virtual Properties <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="conditional-logic-with-virtual-properties" aria-haspopup="dialog" aria-label="Share link: Conditional Logic with Virtual Properties"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Use virtual properties in CASE expressions MATCH (o:Order) RETURN o.id, o.total, o.age_category, CASE o.price_tier WHEN 'luxury' THEN 'Premium Shipping' WHEN 'premium' THEN 'Express Shipping' ELSE 'Standard Shipping' END AS recommended_shipping; -- Complex filtering MATCH (p:Product) WHERE p.in_stock = true AND p.profit_margin_percent > 20 AND p.avg_rating >= 4.0 RETURN p.name, p.formatted_price, p.stock_status, p.rating_display; </code></pre></div> <h3 id="performance-considerations" class="position-relative d-flex align-items-center group"> Performance Considerations <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="performance-considerations" aria-haspopup="dialog" aria-label="Share link: Performance Considerations"> Share link </button> </h3> <h4 id="optimization-strategies" class="position-relative d-flex align-items-center group"> Optimization Strategies <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="optimization-strategies" aria-haspopup="dialog" aria-label="Share link: Optimization Strategies"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- AVOID: Expensive aggregation in virtual property used in WHERE MATCH (u:User) WHERE u.follower_count > 1000 -- Slow if follower_count is virtual RETURN u.name; -- BETTER: Use computed property or index CREATE INDEX idx_user_follower_count ON User(follower_count); -- AVOID: Deep relationship traversal in virtual property VIRTUAL friends_of_friends_count INTEGER AS ( SELECT COUNT(DISTINCT fof) FROM MATCH (this)-[:FRIEND]-()-[:FRIEND]-(fof) ); -- Too expensive! -- BETTER: Limit depth or materialize VIRTUAL direct_friends_count INTEGER AS ( SELECT COUNT(*) FROM MATCH (this)-[:FRIEND]-(f) ); -- Much faster </code></pre></div> <h4 id="caching-virtual-property-results" class="position-relative d-flex align-items-center group"> Caching Virtual Property Results <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="caching-virtual-property-results" aria-haspopup="dialog" aria-label="Share link: Caching Virtual Property Results"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- In application code, cache virtual property results -- Python example: from functools import lru_cache from datetime import datetime, timedelta class User: @property @lru_cache(maxsize=128) def follower_count(self): # Virtual property result cached for 5 minutes return self._calculate_follower_count() # Go example: type User struct { followerCountCache int followerCountExpiry time.Time } func (u *User) FollowerCount() int { if time.Now().Before(u.followerCountExpiry) { return u.followerCountCache } count := u.calculateFollowerCount() u.followerCountCache = count u.followerCountExpiry = time.Now().Add(5 * time.Minute) return count } </code></pre></div> <h3 id="best-practices" class="position-relative d-flex align-items-center group"> Best Practices <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="best-practices" aria-haspopup="dialog" aria-label="Share link: Best Practices"> Share link </button> </h3> <h4 id="design-guidelines" class="position-relative d-flex align-items-center group"> Design Guidelines <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="design-guidelines" aria-haspopup="dialog" aria-label="Share link: Design Guidelines"> Share link </button> </h4><ol> <li>Keep Calculations Simple: Virtual properties should be fast (<10ms)</li> <li>Avoid Deep Traversals: Limit relationship traversal to 1-2 hops</li> <li>Use for Display Logic: Perfect for formatting, not complex business rules</li> <li>Handle NULL Values: Always use COALESCE or CASE for NULL safety</li> <li>Document Purpose: Explain why property is virtual vs computed/stored</li> </ol> <h4 id="when-to-convert-to-computedstored" class="position-relative d-flex align-items-center group"> When to Convert to Computed/Stored <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="when-to-convert-to-computedstored" aria-haspopup="dialog" aria-label="Share link: When to Convert to Computed/Stored"> Share link </button> </h4>Convert to Computed Property If: <ul> <li>Queried frequently (>1000 times/day)</li> <li>Used in WHERE clauses often</li> <li>Need to create index on the property</li> <li>Calculation time > 50ms</li> </ul> Convert to Stored Property If: <ul> <li>Value rarely changes</li> <li>Need guaranteed consistent reads</li> <li>Complex expensive calculation</li> <li>Historical values matter</li> </ul> <h4 id="testing-virtual-properties" class="position-relative d-flex align-items-center group"> Testing Virtual Properties <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="testing-virtual-properties" aria-haspopup="dialog" aria-label="Share link: Testing Virtual Properties"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Test virtual property logic SELECT u.first_name, u.last_name, u.full_name, -- Verify calculation manually u.first_name || ' ' || u.last_name AS expected_full_name FROM User u WHERE u.full_name <> (u.first_name || ' ' || u.last_name) LIMIT 10; -- Should return 0 rows if logic is correct </code></pre></div> <h3 id="common-patterns" class="position-relative d-flex align-items-center group"> Common Patterns <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="common-patterns" aria-haspopup="dialog" aria-label="Share link: Common Patterns"> Share link </button> </h3> <h4 id="default-value-pattern" class="position-relative d-flex align-items-center group"> Default Value Pattern <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="default-value-pattern" aria-haspopup="dialog" aria-label="Share link: Default Value Pattern"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">VIRTUAL display_value STRING AS ( COALESCE(NULLIF(custom_value, ''), default_value, 'N/A') ) </code></pre></div> <h4 id="conditional-display-pattern" class="position-relative d-flex align-items-center group"> Conditional Display Pattern <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="conditional-display-pattern" aria-haspopup="dialog" aria-label="Share link: Conditional Display Pattern"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">VIRTUAL status_display STRING AS ( CASE WHEN condition1 THEN 'Display Text 1' WHEN condition2 THEN 'Display Text 2' ELSE 'Default Display' END ) </code></pre></div> <h4 id="aggregation-pattern" class="position-relative d-flex align-items-center group"> Aggregation Pattern <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="aggregation-pattern" aria-haspopup="dialog" aria-label="Share link: Aggregation Pattern"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">VIRTUAL count_related INTEGER AS ( SELECT COUNT(*) FROM MATCH (this)-[:RELATED]->(related) ) </code></pre></div> <h4 id="formatting-pattern" class="position-relative d-flex align-items-center group"> Formatting Pattern <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="formatting-pattern" aria-haspopup="dialog" aria-label="Share link: Formatting Pattern"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">VIRTUAL formatted_value STRING AS ( prefix || ' ' || CAST(numeric_value AS STRING) || ' ' || suffix ) </code></pre></div> <h3 id="troubleshooting" class="position-relative d-flex align-items-center group"> Troubleshooting <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="troubleshooting" aria-haspopup="dialog" aria-label="Share link: Troubleshooting"> Share link </button> </h3> <h4 id="slow-query-performance" class="position-relative d-flex align-items-center group"> Slow Query Performance <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="slow-query-performance" aria-haspopup="dialog" aria-label="Share link: Slow Query Performance"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Use EXPLAIN to identify slow virtual properties EXPLAIN ANALYZE SELECT u.name, u.virtual_property FROM User u WHERE u.another_virtual_property > 100; -- Profile query execution PROFILE SELECT * FROM User LIMIT 100; -- Check time spent evaluating virtual properties </code></pre></div> <h4 id="null-handling-issues" class="position-relative d-flex align-items-center group"> NULL Handling Issues <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="null-handling-issues" aria-haspopup="dialog" aria-label="Share link: NULL Handling Issues"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Problem: NULL concatenation returns NULL VIRTUAL full_address STRING AS ( street || ', ' || city || ', ' || state ); -- Returns NULL if any field is NULL -- Solution: Use COALESCE VIRTUAL full_address STRING AS ( COALESCE(street, '') || CASE WHEN city IS NOT NULL THEN ', ' || city ELSE '' END || CASE WHEN state IS NOT NULL THEN ', ' || state ELSE '' END ); </code></pre></div> <h3 id="related-topics" class="position-relative d-flex align-items-center group"> Related Topics <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="related-topics" aria-haspopup="dialog" aria-label="Share link: Related Topics"> Share link </button> </h3><ul> <li><a href="/tags/computed-properties/" >Computed Properties</a> - Stored calculated properties</li> <li><a href="/tags/materialized-views/" >Materialized Views</a> - Cached query results</li> <li><a href="/tags/types/" >Types</a> - Type definitions</li> <li><a href="/tags/performance/" >Performance</a> - Query optimization</li> </ul> <h3 id="further-reading" class="position-relative d-flex align-items-center group"> Further Reading <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="further-reading" aria-haspopup="dialog" aria-label="Share link: Further Reading"> Share link </button> </h3><ul> <li><a href="https://oracle-base.com/articles/11g/virtual-columns-11gr1" aria-label="Virtual Columns (Oracle) – opens in new window" target="_blank" rel="noopener noreferrer" >Virtual Columns (Oracle) ↗ </a> - Oracle documentation</li> <li><a href="https://dev.mysql.com/doc/refman/8.0/en/create-table-generated-columns.html" aria-label="Generated Columns (MySQL) – opens in new window" target="_blank" rel="noopener noreferrer" >Generated Columns (MySQL) ↗ </a> - MySQL reference</li> <li><a href="https://docs.microsoft.com/en-us/sql/relational-databases/tables/specify-computed-columns-in-a-table" aria-label="Computed Columns (SQL Server) – opens in new window" target="_blank" rel="noopener noreferrer" >Computed Columns (SQL Server) ↗ </a> - SQL Server guide</li> </ul>

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