Query the Data Delivery Network
Query the DDNThe easiest way to query any data on Splitgraph is via the "Data Delivery Network" (DDN). The DDN is a single endpoint that speaks the PostgreSQL wire protocol. Any Splitgraph user can connect to it at data.splitgraph.com:5432 and query any version of over 40,000 datasets that are hosted or proxied by Splitgraph.
For example, you can query the defaulted_tax_data table in this repository, by referencing it like:
"sonomacounty-ca-gov/defaulted-tax-data-bp8v-uax7:latest"."defaulted_tax_data"or in a full query, like:
SELECT
":id", -- Socrata column ID
"mailaddress1", -- Address line 1 or C/O or DBA (Doing Business As)
"salenoticedate", -- When property becomes 5 years delinquent and the tax collector records the power to sell.
"defaultamt", -- 1st year of defaulted tax and penalties. Base Tax amount + Ten Percent Penalty + Cost Charge
"assessment_roll_year", -- The year the bill was placed on the tax roll.
"location_city_state", -- The city state location of the property.
"collection_code2", -- Set when payment is recorded.
"fullredemptionpaid", -- Prior year taxes paid.
"billednetvalue", -- The billed net value of the assessment.
"billedgrowingimprvalue", -- Assessment billed for agricultural improvements value on property.
"billedmarketlandvalue", -- Bill value. If an original bill, amount represents total value. If original bill is paid, amount represents net change. If reassessment results in a lower value, amount shown could be negative.
"mailaddress3", -- Address line 2 when MailAddress1 is C/O or DBA. In all other cases City, State, zip
"mailaddress2", -- Address line 2 except when MailAddress1 is C/O or DBA.
"defaultnum", -- Systematically assigned number for secured records that go unpaid past their fiscal year.
"secured_delinq_penality_amt_paid", -- The interest calculated for assessment from July 1st of the fiscal year through paid as of date.
"exemption_code1", -- Code = Description, E01 = Homeowner, E04 = Disabled Vet Spouse 100,000, E06 = Disabled Vet 100,000, E08 = Welfare-Charitable, E16 = Cemetery, E17 = Church, E18 = Free Museum/Library, E21 = Public School, E22 = Religious-One Time Filing, E97 = Hox Penalty (used for roll corrections), E99 = Low Value
"billedpersonalpropmhvalue", -- he billed amount of personal property mobile home value on the assessment.
"billedpersonalpropvalue", -- The billed amount of personal property value on the assessment.
"billedfixedimprvalue", -- Assessment billed for fixed improvements value on property.
"taxability", -- Code = Description, 0 = Normal Ownership, 1 = Business, Ownership, 2 = Zero Value Property, 10 = Senior Citizens Postponement, 12 = Low Value Real Property, 34 = Taxable Gov’t Entity Section 11, 44 = Gov’t Restricted Affordable Housing, 50 = Property Under CLCA, 51 = Property under CLCA/Business, 60 = Tax Postponed (Sr Citizens Postponement), 70 = Common Area, 600 = Timber Preserve, 800 = Prop 8 Reduction-Manual, 801 = Prop 8 Reduction w Bus/Manual, 850 = Prop 8 w/Contract CLCA, 860 = Prop 8 Tax Postponed, 870 = Prop 8 Value Uploaded, 871 = Prop 8 Automatic Reduction w/business
"originating_assessment_number", -- The original assessment number on parcel splits.
"originating_assessment", -- The parcel that originated the tax bill.
"assessment_number", -- 1st 3 Characters = Book, 2nd 3 Characters = Page, 3rd 3 Characters = Parcel, 4th 3 Characters = Sub Parcel
"location_address", -- The street address location of the property.
"base_tax_amount", -- Total tax amount for the 2nd installment.
"redeemed_date", -- Date default record is payed.
"feeparcel", -- The parcel where the assessment is located.
"taxyear", -- Tax rate year.
"tax_rate_area", -- The original tax rate area for a delinquent assessment.
"exemption_amount2", -- The amount of the exemption
"mailaddress4", -- Address line 3 when MailAddr1 is C/O or DBA.
"paid_amount", -- This represents the tax amount paid - Base_Tax_Amount + Ten_Percent_Penalty_Amount (if paid) + Cost_Charge (if paid) for redemptions.
"isagpreserve", -- The property is an agricultural preserve.
"default_date", -- The date the assessment defaulted.
"ten_percent_penality_amount", -- Penalty amount for the Base_Tax_Amount. Always set, delinquent or not.
"exemption_amount1", -- The amount of the exemption.
"billedstructuralimprvalue", -- Assessment billed for structural improvements value on property.
"redemption_fee",
"bill_date", -- The date the bill was printed.
"exemption_code2", -- Code = Description, E01 = Homeowner, E04 = Disabled Vet Spouse 100,000, E06 = Disabled Vet 100,000, E08 = Welfare-Charitable, E16 = Cemetery, E17 = Church, E18 = Free Museum/Library, E21 = Public School, E22 = Religious-One Time Filing, E97 = Hox Penalty (used for roll corrections), E99 = Low Value
"existsbankruptcy", -- A bankruptcy exists on the assessment.
"cost_charge", -- Second installment penalty cost charge.
"redemptiontotalfees" -- Total redemption fees paid.
FROM
"sonomacounty-ca-gov/defaulted-tax-data-bp8v-uax7:latest"."defaulted_tax_data"
LIMIT 100;Connecting to the DDN is easy. All you need is an existing SQL client that can connect to Postgres. As long as you have a SQL client ready, you'll be able to query sonomacounty-ca-gov/defaulted-tax-data-bp8v-uax7 with SQL in under 60 seconds.
Query Your Local Engine
bash -c "$(curl -sL https://github.com/splitgraph/splitgraph/releases/latest/download/install.sh)"Read the installation docs.
Splitgraph Cloud is built around Splitgraph Core (GitHub), which includes a local Splitgraph Engine packaged as a Docker image. Splitgraph Cloud is basically a scaled-up version of that local Engine. When you query the Data Delivery Network or the REST API, we mount the relevant datasets in an Engine on our servers and execute your query on it.
It's possible to run this engine locally. You'll need a Mac, Windows or Linux system to install sgr, and a Docker installation to run the engine. You don't need to know how to actually use Docker; sgrcan manage the image, container and volume for you.
There are a few ways to ingest data into the local engine.
For external repositories, the Splitgraph Engine can "mount" upstream data sources by using sgr mount. This feature is built around Postgres Foreign Data Wrappers (FDW). You can write custom "mount handlers" for any upstream data source. For an example, we blogged about making a custom mount handler for HackerNews stories.
For hosted datasets (like this repository), where the author has pushed Splitgraph Images to the repository, you can "clone" and/or "checkout" the data using sgr cloneand sgr checkout.
Cloning Data
Because sonomacounty-ca-gov/defaulted-tax-data-bp8v-uax7:latest is a Splitgraph Image, you can clone the data from Spltgraph Cloud to your local engine, where you can query it like any other Postgres database, using any of your existing tools.
First, install Splitgraph if you haven't already.
Clone the metadata with sgr clone
This will be quick, and does not download the actual data.
sgr clone sonomacounty-ca-gov/defaulted-tax-data-bp8v-uax7Checkout the data
Once you've cloned the data, you need to "checkout" the tag that you want. For example, to checkout the latest tag:
sgr checkout sonomacounty-ca-gov/defaulted-tax-data-bp8v-uax7:latestThis will download all the objects for the latest tag of sonomacounty-ca-gov/defaulted-tax-data-bp8v-uax7 and load them into the Splitgraph Engine. Depending on your connection speed and the size of the data, you will need to wait for the checkout to complete. Once it's complete, you will be able to query the data like you would any other Postgres database.
Alternatively, use "layered checkout" to avoid downloading all the data
The data in sonomacounty-ca-gov/defaulted-tax-data-bp8v-uax7:latest is 0 bytes. If this is too big to download all at once, or perhaps you only need to query a subset of it, you can use a layered checkout.:
sgr checkout --layered sonomacounty-ca-gov/defaulted-tax-data-bp8v-uax7:latestThis will not download all the data, but it will create a schema comprised of foreign tables, that you can query as you would any other data. Splitgraph will lazily download the required objects as you query the data. In some cases, this might be faster or more efficient than a regular checkout.
Read the layered querying documentation to learn about when and why you might want to use layered queries.
Query the data with your existing tools
Once you've loaded the data into your local Splitgraph Engine, you can query it with any of your existing tools. As far as they're concerned, sonomacounty-ca-gov/defaulted-tax-data-bp8v-uax7 is just another Postgres schema.