@ -47,7 +47,7 @@
"execution_count": 1,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td>status</td></tr></thead><tbody><tr><td>OK</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 1 ms</span></div>"
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\" >status</td></tr></thead><tbody><tr><td>OK</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 9 ms</span></div>"
},
"metadata": {}
}
@ -80,7 +80,7 @@
"execution_count": 2,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td>a</td><td>b</td></tr></thead><tbody><tr><td>alice</td><td>eve</td></tr><tr><td>bob</td><td>alice</td></tr><tr><td>charlie</td><td>eve</td></tr><tr><td>david</td><td>george</td></tr><tr><td>eve</td><td>alice</td></tr><tr><td>eve</td><td>bob</td></tr><tr><td>eve</td><td>charlie</td></tr><tr><td>george</td><td>george</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0 ms</span></div>"
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\" >a</td><td style=\"font-weight: bold\" >b</td></tr></thead><tbody><tr><td>alice</td><td>eve</td></tr><tr><td>bob</td><td>alice</td></tr><tr><td>charlie</td><td>eve</td></tr><tr><td>david</td><td>george</td></tr><tr><td>eve</td><td>alice</td></tr><tr><td>eve</td><td>bob</td></tr><tr><td>eve</td><td>charlie</td></tr><tr><td>george</td><td>george</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 3 ms</span></div>"
},
"metadata": {}
}
@ -108,7 +108,7 @@
"execution_count": 3,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td>status</td></tr></thead><tbody><tr><td>OK</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0 ms</span></div>"
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\" >status</td></tr></thead><tbody><tr><td>OK</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 2 ms</span></div>"
},
"metadata": {}
}
@ -126,7 +126,7 @@
"execution_count": 4,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td>a</td><td>b</td></tr></thead><tbody><tr><td>alice</td><td>eve</td></tr><tr><td>bob</td><td>alice</td></tr><tr><td>charlie</td><td>eve</td></tr><tr><td>david</td><td>george</td></tr><tr><td>eve</td><td>alice</td></tr><tr><td>eve</td><td>bob</td></tr><tr><td>eve</td><td>charlie</td></tr><tr><td>fred</td><td>alice</td></tr><tr><td>fred</td><td>eve</td></tr><tr><td>george</td><td>george</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0 ms</span></div>"
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\" >a</td><td style=\"font-weight: bold\" >b</td></tr></thead><tbody><tr><td>alice</td><td>eve</td></tr><tr><td>bob</td><td>alice</td></tr><tr><td>charlie</td><td>eve</td></tr><tr><td>david</td><td>george</td></tr><tr><td>eve</td><td>alice</td></tr><tr><td>eve</td><td>bob</td></tr><tr><td>eve</td><td>charlie</td></tr><tr><td>fred</td><td>alice</td></tr><tr><td>fred</td><td>eve</td></tr><tr><td>george</td><td>george</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 2 ms</span></div>"
},
"metadata": {}
}
@ -154,7 +154,7 @@
"execution_count": 5,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td>status</td></tr></thead><tbody><tr><td>OK</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0 ms</span></div>"
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\" >status</td></tr></thead><tbody><tr><td>OK</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 2 ms</span></div>"
},
"metadata": {}
}
@ -172,7 +172,7 @@
"execution_count": 6,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td>a</td><td>b</td></tr></thead><tbody><tr><td>alice</td><td>eve</td></tr><tr><td>bob</td><td>alice</td></tr><tr><td>charlie</td><td>eve</td></tr><tr><td>david</td><td>george</td></tr><tr><td>eve</td><td>bob</td></tr><tr><td>fred</td><td>alice</td></tr><tr><td>fred</td><td>eve</td></tr><tr><td>george</td><td>george</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0 ms</span></div>"
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\" >a</td><td style=\"font-weight: bold\" >b</td></tr></thead><tbody><tr><td>alice</td><td>eve</td></tr><tr><td>bob</td><td>alice</td></tr><tr><td>charlie</td><td>eve</td></tr><tr><td>david</td><td>george</td></tr><tr><td>eve</td><td>bob</td></tr><tr><td>fred</td><td>alice</td></tr><tr><td>fred</td><td>eve</td></tr><tr><td>george</td><td>george</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 3 ms</span></div>"
},
"metadata": {}
}
@ -200,7 +200,7 @@
"execution_count": 7,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td>status</td></tr></thead><tbody><tr><td>OK</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0 ms</span></div>"
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\" >status</td></tr></thead><tbody><tr><td>OK</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 2 ms</span></div>"
},
"metadata": {}
}
@ -218,7 +218,7 @@
"execution_count": 8,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td>a</td><td>b</td></tr></thead><tbody><tr><td>eve</td><td>alice</td></tr><tr><td>eve</td><td>charlie</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0 ms</span></div>"
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\" >a</td><td style=\"font-weight: bold\" >b</td></tr></thead><tbody><tr><td>eve</td><td>alice</td></tr><tr><td>eve</td><td>charlie</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 2 ms</span></div>"
},
"metadata": {}
}
@ -246,7 +246,7 @@
"execution_count": 9,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td>name</td><td>arity</td></tr></thead><tbody><tr><td>triangles</td><td><span style=\"color: #307fc1;\">2</span></td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0ms</span></div>"
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\" >name</td><td style=\"font-weight: bold\" >arity</td></tr></thead><tbody><tr><td>triangles</td><td><span style=\"color: #307fc1;\">2</span></td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0ms</span></div>"
},
"metadata": {}
}
@ -254,12 +254,12 @@
},
{
"cell_type": "markdown",
"source": "Now this triangles business is becoming tiring. Let's get rid of it :",
"source": "Relations can be renamed :",
"metadata": {}
},
{
"cell_type": "code",
"source": ":db remov e relation triangles",
"source": ":db rena me relation triangles love_ triangles",
"metadata": {
"trusted": true
},
@ -269,7 +269,66 @@
"execution_count": 10,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td>status</td></tr></thead><tbody><tr><td>OK</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0ms</span></div>"
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">status</td></tr></thead><tbody><tr><td>OK</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0ms</span></div>"
},
"metadata": {}
}
]
},
{
"cell_type": "code",
"source": ":db relations",
"metadata": {
"trusted": true
},
"execution_count": 11,
"outputs": [
{
"execution_count": 11,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">name</td><td style=\"font-weight: bold\">arity</td></tr></thead><tbody><tr><td>love_triangles</td><td><span style=\"color: #307fc1;\">2</span></td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0ms</span></div>"
},
"metadata": {}
}
]
},
{
"cell_type": "code",
"source": "?[a, b] := :love_triangles[a, b]",
"metadata": {
"trusted": true
},
"execution_count": 12,
"outputs": [
{
"execution_count": 12,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">a</td><td style=\"font-weight: bold\">b</td></tr></thead><tbody><tr><td>eve</td><td>alice</td></tr><tr><td>eve</td><td>charlie</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 3ms</span></div>"
},
"metadata": {}
}
]
},
{
"cell_type": "markdown",
"source": "Now this triangles business is becoming tiring. Let's get rid of it:",
"metadata": {}
},
{
"cell_type": "code",
"source": ":db remove relation love_triangles",
"metadata": {
"trusted": true
},
"execution_count": 13,
"outputs": [
{
"execution_count": 13,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">status</td></tr></thead><tbody><tr><td>OK</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0ms</span></div>"
},
"metadata": {}
}
@ -282,17 +341,17 @@
},
{
"cell_type": "code",
"source": "?[a, b] := :triangles[a, b]",
"source": "?[a, b] := :love_ triangles[a, b]",
"metadata": {
"trusted": true
},
"execution_count": 11 ,
"execution_count": 14 ,
"outputs": [
{
"execution_count": 11 ,
"execution_count": 14 ,
"output_type": "execute_result",
"data": {
"text/html": "<pre style=\"font-size: small\"><span style='color:#a00'>query::relation_not_found</span>\n\n <span style='color:#a00'>× \n ╭────\n <span style='opacity:0.67'>1</span> │ ?[a, b] := :triangles[a, b]\n · <span style='color:#a0a'><b> ──────────</b></span>\n ╰──── \n</pre>"
"text/html": "<pre style=\"font-size: small\"><span style='color:#a00'>query::relation_not_found</span>\n\n <span style='color:#a00'>× love_ triangles'\n</pre>"
},
"metadata": {}
}
@ -315,42 +374,42 @@
},
{
"cell_type": "markdown",
"source": "But your _business_ data is mostly likely not as simple as that. At this age of BigDataⒸ, you must have one billion active users on your platforms carrying out all sorts of activities, concurrently of course. You don't want these activities to step on each other. You don't want to store the wrong thing into your user's accounts. You _especially_ don't want any money in transit to disappear in midair. To make things worse, hundreds of new activities pop up each day. \n\nYou don't want to store any of those in a stored relation . With a traditional RDBMS, [data migrations](https://en.wikipedia.org/wiki/Data_migration) would have already killed you. And with Cozo, stored relations don't even try to support schema change (in fact, the only 'schema' for a stored relation is its arity).\n\nSo let's step back a bit and recap what we want in this case :\n\n* high concurrency;\n* fine-grained transactions;\n* checks for data integrity;\n* ability to rapidly adapt to changing data shapes.\n\nBut at what cost? We have to give up something, right? Here are the prices we are willing to pay in this case:\n\n* we restrict most transactions to _local changes_: i.e. they only touch on a tiny fraction of the data;\n* we can tolerate levels of indirections .",
"source": "But your _business_ data is mostly likely not as simple as that. At this age of BigDataⒸ, you must have one billion active users on your platforms carrying out all sorts of activities, concurrently of course. You don't want these activities to step on each other. You don't want to store the wrong thing into your user's accounts. You _especially_ don't want any money in transit to disappear in midair. To make things worse, hundreds of new activities pop up each day. \n\nStoring any of these in a stored relation is infeasible . With a traditional RDBMS, [data migrations](https://en.wikipedia.org/wiki/Data_migration) would have already killed you. And with Cozo, stored relations don't even try to support schema change (in fact, the only 'schema' for a stored relation is its arity).\n\nTo store such data and meet its query and mutation requirements, a database needs :\n\n* high concurrency;\n* fine-grained transactions;\n* checks for data integrity;\n* ability to rapidly adapt to new data shapes and requirements.\n\nBut in turn, we have to give up something. So with Cozo, we are willing to pay the following prices:\n\n* we demand that most transactions only apply _local changes_ that only touch on a tiny fraction of the data (otherwise the database cannot satisfy the high concurrency requirements);\n* we tolerate indirections (since \"all problems in computer science can be solved by another level of indirection\") .",
"metadata": {}
},
{
"cell_type": "markdown",
"source": "After we've paid our price we got our solution. It is a very old solution actually: the [triple store](https://en.wikipedia.org/wiki/Triplestore).",
"source": "The solution is the [triple store](https://en.wikipedia.org/wiki/Triplestore).",
"metadata": {}
},
{
"cell_type": "markdown",
"source": "The idea is very simple. a _triple_ is a sentence consisting of a subject, a verb, and an object. In the Cozo flavour, the subject is always an opaque identity, such as _entity42_. The following are examples of triples in this sense :\n\n* _entity42_ has first name `'Alice'`.\n* _entity42_ has last name `'Liddell'`.\n* _entity42_ loves _entity81_.\n* _entity81_ is aged `20` years old.",
"source": "A _triple_ is a sentence consisting of a subject, a verb, and an object. In the Cozo flavour, the subject is always an opaque identity, such as _entity42_, so it is actually an _entity-attribute-value_ triple. Examples :\n\n* _entity42_ has first name `'Alice'`.\n* _entity42_ has last name `'Liddell'`.\n* _entity42_ loves _entity81_.\n* _entity81_ is aged `20` years old.",
"metadata": {}
},
{
"cell_type": "markdown",
"source": "We put schema into triples by schematize the verbs. We see that in our cas e, the schema for first name and last name should have type strings, the schema for age should have type integers, and the schema for the \"loves\" relationship should be other entities. Here the types refer to the objects in the triple, since the subject is always an entity.",
"source": "We schematize triples by schematizing the verbs (attributes). In our exampl e, the schema for first name and last name should have type strings, the schema for age should have type integers, and the schema for the \"loves\" relationship should be other entities. Here the types refer to the objects in the triple, since the subject is always an entity.",
"metadata": {}
},
{
"cell_type": "markdown",
"source": "So let's finally put this into code:",
"source": "So let's put this into code:",
"metadata": {}
},
{
"cell_type": "code",
"source": ":schema\n\nput person {\n first_name: string index,\n last_name: string index,\n loves: ref many,\n age: int\n}",
"source": ":schema\n\nput person {\n first_name: string index,\n nick_name: string many index,\n loves: ref many,\n age: int\n}",
"metadata": {
"trusted": true
},
"execution_count": 12 ,
"execution_count": 15 ,
"outputs": [
{
"execution_count": 12 ,
"execution_count": 15 ,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td>attr_id</td><td>op</td></tr></thead><tbody><tr><td><span style=\"color: #307fc1;\">10000001</span></td><td>assert</td></tr><tr><td><span style=\"color: #307fc1;\">10000002</span></td><td>assert</td></tr><tr><td><span style=\"color: #307fc1;\">10000003</span></td><td>assert</td></tr><tr><td><span style=\"color: #307fc1;\">10000004</span></td><td>assert</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0 ms</span></div>"
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\" >attr_id</td><td style=\"font-weight: bold\" >op</td></tr></thead><tbody><tr><td><span style=\"color: #307fc1;\">10000001</span></td><td>assert</td></tr><tr><td><span style=\"color: #307fc1;\">10000002</span></td><td>assert</td></tr><tr><td><span style=\"color: #307fc1;\">10000003</span></td><td>assert</td></tr><tr><td><span style=\"color: #307fc1;\">10000004</span></td><td>assert</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 1 ms</span></div>"
},
"metadata": {}
}
@ -358,7 +417,7 @@
},
{
"cell_type": "markdown",
"source": "Let's explain. The `:schema` at the top indicates that we want to manage the schema instead of run normal queries. We then `put` a _group_ of related schema. Now even though they are declared together similarly to a table definition in SQL, we need to stress that this actually defines four separate, independent attributes named `person.first_name`, `person.last_name`, `person.loves`, `person.age`. An entity can have whatever attributes associated with it, even those with different prefixes.",
"source": "The `:schema` at the top indicates that we want to manage the schema instead of run normal queries. We then `put` a _group_ of related schema. Now even though they are declared together similarly to a table definition in SQL, we need to stress that this actually defines four separate, independent attributes named `person.first_name`, `person.last_name`, `person.loves`, `person.age`. An entity can have whatever attributes associated with it, even those with different prefixes.",
"metadata": {}
},
{
@ -368,7 +427,7 @@
},
{
"cell_type": "markdown",
"source": "Instead of `index`, we can mark attributes with the modifier `unique`, indicating there cannot be two entities with the same value for the attribute. The value then acts as an _unique identifier_ for the entity, which is convenient in certain circumstanc es since the entity ID is assigned by the database automatically and you cannot choose it. So let's add an explicit `person.id` attribute, this time using the non-grouped syntax:",
"source": "Instead of `index`, we can mark attributes with the modifier `unique`, indicating there cannot be two entities with the same value for the attribute. The value then acts as an _unique identifier_ for the entity, which can be convenient when retrieving the entiti es since the entity ID is assigned by the database automatically and you cannot choose how it is assigned . So let's add an explicit `person.id` attribute, this time using the non-grouped syntax:",
"metadata": {}
},
{
@ -377,13 +436,13 @@
"metadata": {
"trusted": true
},
"execution_count": 13 ,
"execution_count": 16 ,
"outputs": [
{
"execution_count": 13 ,
"execution_count": 16 ,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td>attr_id</td><td>op</td></tr></thead><tbody><tr><td><span style=\"color: #307fc1;\">10000005</span></td><td>assert</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0ms</span></div>"
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\" >attr_id</td><td style=\"font-weight: bold\" >op</td></tr></thead><tbody><tr><td><span style=\"color: #307fc1;\">10000005</span></td><td>assert</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0ms</span></div>"
},
"metadata": {}
}
@ -400,23 +459,442 @@
"metadata": {
"trusted": true
},
"execution_count": 1,
"execution_count": 17 ,
"outputs": [
{
"execution_count": 1,
"execution_count": 17,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">attr_id</td><td style=\"font-weight: bold\">name</td><td style=\"font-weight: bold\">type</td><td style=\"font-weight: bold\">cardinality</td><td style=\"font-weight: bold\">index</td><td style=\"font-weight: bold\">history</td></tr></thead><tbody><tr><td><span style=\"color: #307fc1;\">10000001</span></td><td>person.first_name</td><td>string</td><td>one</td><td>index</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr><tr><td><span style=\"color: #307fc1;\">10000002</span></td><td>person.nick_name</td><td>string</td><td>many</td><td>index</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr><tr><td><span style=\"color: #307fc1;\">10000003</span></td><td>person.loves</td><td>ref</td><td>many</td><td>none</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr><tr><td><span style=\"color: #307fc1;\">10000004</span></td><td>person.age</td><td>int</td><td>one</td><td>none</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr><tr><td><span style=\"color: #307fc1;\">10000005</span></td><td>person.id</td><td>string</td><td>one</td><td>unique</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0ms</span></div>"
},
"metadata": {}
}
]
},
{
"cell_type": "markdown",
"source": "We can rename the attribute:",
"metadata": {}
},
{
"cell_type": "code",
"source": ":db rename attr person.id person.pid",
"metadata": {
"trusted": true
},
"execution_count": 18,
"outputs": [
{
"execution_count": 18,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">attr_id</td><td style=\"font-weight: bold\">name</td><td style=\"font-weight: bold\">type</td><td style=\"font-weight: bold\">cardinality</td><td style=\"font-weight: bold\">index</td><td style=\"font-weight: bold\">history</td></tr></thead><tbody><tr><td><span style=\"color: #307fc1;\">10000001</span></td><td>person.first_name</td><td>string</td><td>one</td><td>index</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr><tr><td><span style=\"color: #307fc1;\">10000002</span></td><td>person.last_name</td><td>string</td><td>one</td><td>index</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr><tr><td><span style=\"color: #307fc1;\">10000003</span></td><td>person.loves</td><td>ref</td><td>many</td><td>none</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr><tr><td><span style=\"color: #307fc1;\">10000004</span></td><td>person.age</td><td>int</td><td>one</td><td>none</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr><tr><td><span style=\"color: #307fc1;\">10000005</span></td><td>person</td><td>string</td><td>one</td><td>unique</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0ms</span></div>"
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">status</td></tr></thead><tbody><tr><td>OK</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0ms</span></div>"
},
"metadata": {}
}
]
},
{
"cell_type": "code",
"source": ":db schema",
"metadata": {
"trusted": true
},
"execution_count": 19,
"outputs": [
{
"execution_count": 19,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">attr_id</td><td style=\"font-weight: bold\">name</td><td style=\"font-weight: bold\">type</td><td style=\"font-weight: bold\">cardinality</td><td style=\"font-weight: bold\">index</td><td style=\"font-weight: bold\">history</td></tr></thead><tbody><tr><td><span style=\"color: #307fc1;\">10000001</span></td><td>person.first_name</td><td>string</td><td>one</td><td>index</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr><tr><td><span style=\"color: #307fc1;\">10000002</span></td><td>person.nick_name</td><td>string</td><td>many</td><td>index</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr><tr><td><span style=\"color: #307fc1;\">10000003</span></td><td>person.loves</td><td>ref</td><td>many</td><td>none</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr><tr><td><span style=\"color: #307fc1;\">10000004</span></td><td>person.age</td><td>int</td><td>one</td><td>none</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr><tr><td><span style=\"color: #307fc1;\">10000005</span></td><td>person.pid</td><td>string</td><td>one</td><td>unique</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0ms</span></div>"
},
"metadata": {}
}
]
},
{
"cell_type": "markdown",
"source": "As well as getting rid of it (this will remove all the data associated with the attribute as well):",
"metadata": {}
},
{
"cell_type": "code",
"source": ":db remove attr person.pid",
"metadata": {
"trusted": true
},
"execution_count": 20,
"outputs": [
{
"execution_count": 20,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">status</td></tr></thead><tbody><tr><td>OK</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0ms</span></div>"
},
"metadata": {}
}
]
},
{
"cell_type": "code",
"source": ":db schema",
"metadata": {
"trusted": true
},
"execution_count": 21,
"outputs": [
{
"execution_count": 21,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">attr_id</td><td style=\"font-weight: bold\">name</td><td style=\"font-weight: bold\">type</td><td style=\"font-weight: bold\">cardinality</td><td style=\"font-weight: bold\">index</td><td style=\"font-weight: bold\">history</td></tr></thead><tbody><tr><td><span style=\"color: #307fc1;\">10000001</span></td><td>person.first_name</td><td>string</td><td>one</td><td>index</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr><tr><td><span style=\"color: #307fc1;\">10000002</span></td><td>person.nick_name</td><td>string</td><td>many</td><td>index</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr><tr><td><span style=\"color: #307fc1;\">10000003</span></td><td>person.loves</td><td>ref</td><td>many</td><td>none</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr><tr><td><span style=\"color: #307fc1;\">10000004</span></td><td>person.age</td><td>int</td><td>one</td><td>none</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 1ms</span></div>"
},
"metadata": {}
}
]
},
{
"cell_type": "markdown",
"source": "But that's about it. Except its name, an attribute is _immutable_ and you cannot change a `string` attribute to a `ref` attribute, nor can you decide that your `one` attribute should really be `many`.\n\nSo what do we mean when we said that this kind of structure can deal with new requirements? Say you initially made the `person.loves` attribute one-to-one and made `person.last_name` a unique index, and now you need to change them. But you need to change them not because the requirements have changed. You need to change them because you have made _mistakes_ at the beginning. These mistakes are fixed by, for example, first rename the offending attributes, then create a new attribute with the old name, next copy the data from the old attribute to the new attribute, and finally delete the old, wrong attribute. Fixing mistakes should be explicit, and this is procedure is very explicit.",
"metadata": {}
},
{
"cell_type": "markdown",
"source": "New requirements are not mistakes, and they do not invalidate your old data or schema. Examples of changing requirements: you now need to record the passport number and the parent-child relationships of the people in your graph. Very easy:",
"metadata": {}
},
{
"cell_type": "code",
"source": ":schema\n\nput person.passport_no: string many index;\nput person.parent_of: ref many;",
"metadata": {
"trusted": true
},
"execution_count": 22,
"outputs": [
{
"execution_count": 22,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">attr_id</td><td style=\"font-weight: bold\">op</td></tr></thead><tbody><tr><td><span style=\"color: #307fc1;\">10000006</span></td><td>assert</td></tr><tr><td><span style=\"color: #307fc1;\">10000007</span></td><td>assert</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 1ms</span></div>"
},
"metadata": {}
}
]
},
{
"cell_type": "code",
"source": ":db schema",
"metadata": {
"trusted": true
},
"execution_count": 23,
"outputs": [
{
"execution_count": 23,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">attr_id</td><td style=\"font-weight: bold\">name</td><td style=\"font-weight: bold\">type</td><td style=\"font-weight: bold\">cardinality</td><td style=\"font-weight: bold\">index</td><td style=\"font-weight: bold\">history</td></tr></thead><tbody><tr><td><span style=\"color: #307fc1;\">10000001</span></td><td>person.first_name</td><td>string</td><td>one</td><td>index</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr><tr><td><span style=\"color: #307fc1;\">10000002</span></td><td>person.nick_name</td><td>string</td><td>many</td><td>index</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr><tr><td><span style=\"color: #307fc1;\">10000003</span></td><td>person.loves</td><td>ref</td><td>many</td><td>none</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr><tr><td><span style=\"color: #307fc1;\">10000004</span></td><td>person.age</td><td>int</td><td>one</td><td>none</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr><tr><td><span style=\"color: #307fc1;\">10000006</span></td><td>person.passport_no</td><td>string</td><td>many</td><td>index</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr><tr><td><span style=\"color: #307fc1;\">10000007</span></td><td>person.parent_of</td><td>ref</td><td>many</td><td>none</td><td><span style=\"color: #bf5b3d;\">false</span></td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0ms</span></div>"
},
"metadata": {}
}
]
},
{
"cell_type": "markdown",
"source": "## Data with schema",
"metadata": {}
},
{
"cell_type": "markdown",
"source": "Let's reinstate the `person.id` attribute first:",
"metadata": {}
},
{
"cell_type": "code",
"source": ":schema\n\nput person.id: string one unique;",
"metadata": {
"trusted": true
},
"execution_count": 24,
"outputs": [
{
"execution_count": 24,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">attr_id</td><td style=\"font-weight: bold\">op</td></tr></thead><tbody><tr><td><span style=\"color: #307fc1;\">10000008</span></td><td>assert</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0ms</span></div>"
},
"metadata": {}
}
]
},
{
"cell_type": "markdown",
"source": "and now we add data to our database. First we add a person called Peter. Besides the `:tx` at the top indicating that we want to execute a transaction, it is just a map:",
"metadata": {}
},
{
"cell_type": "code",
"source": ":tx\n\n{ person.first_name: 'Peter', person.nick_name: 'Pan', person.id: 'p' }",
"metadata": {
"trusted": true
},
"execution_count": 25,
"outputs": [
{
"execution_count": 25,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">entity_id</td><td style=\"font-weight: bold\">asserts</td><td style=\"font-weight: bold\">retracts</td></tr></thead><tbody><tr><td>550dad48-3501-11ed-8dc9-9aefd164fdd2</td><td><span style=\"color: #307fc1;\">3</span></td><td><span style=\"color: #307fc1;\">0</span></td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 2ms</span></div>"
},
"metadata": {}
}
]
},
{
"cell_type": "markdown",
"source": "You can insert multiple 'rows' at the same time, and the maps also allow some stylistic variations:",
"metadata": {}
},
{
"cell_type": "code",
"source": ":tx\n\n{\"person.first_name\": \"Quin\", \"*person.nick_name\": [\"Q\", \"The Quick\"], \"person.id\": \"q\"}\n{\"person.first_name\": \"Rich\", \"person.id\": \"r\"}",
"metadata": {
"trusted": true
},
"execution_count": 26,
"outputs": [
{
"execution_count": 26,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">entity_id</td><td style=\"font-weight: bold\">asserts</td><td style=\"font-weight: bold\">retracts</td></tr></thead><tbody><tr><td>567c963a-3501-11ed-9c95-82ccbc12f696</td><td><span style=\"color: #307fc1;\">4</span></td><td><span style=\"color: #307fc1;\">0</span></td></tr><tr><td>567c9806-3501-11ed-8e7b-d4c62ea1da21</td><td><span style=\"color: #307fc1;\">2</span></td><td><span style=\"color: #307fc1;\">0</span></td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 4ms</span></div>"
},
"metadata": {}
}
]
},
{
"cell_type": "markdown",
"source": "Every entity is free to have any combination of attributes suitable for it. Note how we specified several nicknames for Quin at the same time, and Rich does not have a nickname.",
"metadata": {}
},
{
"cell_type": "markdown",
"source": "To query the triples, use _triple rules_: these look like a list of three items, except there is no comma inside. The first slot contains the _entity id_ assigned by the system, the middle symbol is the attribute name and must be explicit (can't be a variable), and the last slot contains the value for the attribute:",
"metadata": {}
},
{
"cell_type": "code",
"source": "?[eid, first_name, nick_name] := [eid person.nick_name nick_name], [eid person.first_name first_name]",
"metadata": {
"trusted": true
},
"execution_count": 27,
"outputs": [
{
"execution_count": 27,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">eid</td><td style=\"font-weight: bold\">first_name</td><td style=\"font-weight: bold\">nick_name</td></tr></thead><tbody><tr><td>550dad48-3501-11ed-8dc9-9aefd164fdd2</td><td>Peter</td><td>Pan</td></tr><tr><td>567c963a-3501-11ed-9c95-82ccbc12f696</td><td>Quin</td><td>Q</td></tr><tr><td>567c963a-3501-11ed-9c95-82ccbc12f696</td><td>Quin</td><td>The Quick</td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 3ms</span></div>"
},
"metadata": {}
}
]
},
{
"cell_type": "markdown",
"source": "Besides the above _explicit querying_, there is another way to get attributes associated with an entity: you may specify an _pull directive_ which will expand an integer (interpreted as an entity ID) into a map containing its specified attributes. Observe:",
"metadata": {}
},
{
"cell_type": "code",
"source": "?[pid, eid] := [eid person.id pid]\n\n:pull eid {person.first_name, person.nick_name, person.age}",
"metadata": {
"trusted": true
},
"execution_count": 28,
"outputs": [
{
"execution_count": 28,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">pid</td><td style=\"font-weight: bold\">eid</td></tr></thead><tbody><tr><td>p</td><td><span style=\"color: #bf5b3d;\">{"_id":"550dad48-3501-11ed-8dc9-9aefd164fdd2","person.age":null,"person.first_name":"Peter","person.nick_name":["Pan"]}</span></td></tr><tr><td>q</td><td><span style=\"color: #bf5b3d;\">{"_id":"567c963a-3501-11ed-9c95-82ccbc12f696","person.age":null,"person.first_name":"Quin","person.nick_name":["Q","The Quick"]}</span></td></tr><tr><td>r</td><td><span style=\"color: #bf5b3d;\">{"_id":"567c9806-3501-11ed-8e7b-d4c62ea1da21","person.age":null,"person.first_name":"Rich","person.nick_name":[]}</span></td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 3ms</span></div>"
},
"metadata": {}
}
]
},
{
"cell_type": "markdown",
"source": "If you have several entry bindings that are entities, you can specify several `:pull` directives one after another, but each output binding can have at most one pull directive associated with it.",
"metadata": {}
},
{
"cell_type": "markdown",
"source": "Another notable thing is that pulls always return a map, even if some of the requested attributes are missing for the entity (they are filled with `null` instead). In constrast, observe that the query not using pull directive did not return Rich, but returned Quin twice. As can be seen above, the pull also deals with to-many relationships automatically.",
"metadata": {}
},
{
"cell_type": "markdown",
"source": "Pulls can have nested directives (see the manual for details) and can traverse `ref` triples in the reverse direction. But otherwise pull directives are kept deliberately simple. They are only intended for output processing. If you want recursions, non-trivial filters and the like, do it in the Datalog query instead.",
"metadata": {}
},
{
"cell_type": "markdown",
"source": "Insertions in the triple store actually amounts to _assertions_ of facts. If two conflicting facts are asserted, the last one wins:",
"metadata": {}
},
{
"cell_type": "code",
"source": ":tx\n\n{_key: ['person.id', 'p'], person.first_name: \"Pete\"}",
"metadata": {
"trusted": true
},
"execution_count": 29,
"outputs": [
{
"execution_count": 29,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">entity_id</td><td style=\"font-weight: bold\">asserts</td><td style=\"font-weight: bold\">retracts</td></tr></thead><tbody><tr><td>550dad48-3501-11ed-8dc9-9aefd164fdd2</td><td><span style=\"color: #307fc1;\">1</span></td><td><span style=\"color: #307fc1;\">0</span></td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 2ms</span></div>"
},
"metadata": {}
}
]
},
{
"cell_type": "code",
"source": "?[pid, eid] := [eid person.id pid], pid == 'p'\n\n:pull eid {person.first_name, person.nick_name}",
"metadata": {
"trusted": true
},
"execution_count": 40,
"outputs": [
{
"execution_count": 40,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">pid</td><td style=\"font-weight: bold\">eid</td></tr></thead><tbody><tr><td>p</td><td><span style=\"color: #bf5b3d;\">{"_id":"550dad48-3501-11ed-8dc9-9aefd164fdd2","person.first_name":"Pete","person.nick_name":["Pan","Ping"]}</span></td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 3ms</span></div>"
},
"metadata": {}
}
]
},
{
"cell_type": "markdown",
"source": "Here we specified an existing entity by providing `_key` with an attribute name and a unique value for the attribute. You can only refer to entities this way if the attribute is uniquely indexed. You can also specify an entity by providing its `_id`, but if you have a unique key to use, it is often much clearer.",
"metadata": {}
},
{
"cell_type": "markdown",
"source": "The next transaction is superficially similar to the last one. But in this case, `person.nick_name` has cardinality `many` instead of `one`:",
"metadata": {}
},
{
"cell_type": "code",
"source": ":tx\n\n{_key: ['person.id', 'p'], person.nick_name: \"Ping\"}",
"metadata": {
"trusted": true
},
"execution_count": 33,
"outputs": [
{
"execution_count": 33,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">entity_id</td><td style=\"font-weight: bold\">asserts</td><td style=\"font-weight: bold\">retracts</td></tr></thead><tbody><tr><td>550dad48-3501-11ed-8dc9-9aefd164fdd2</td><td><span style=\"color: #307fc1;\">1</span></td><td><span style=\"color: #307fc1;\">0</span></td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 2ms</span></div>"
},
"metadata": {}
}
]
},
{
"cell_type": "code",
"source": "?[pid, eid] := [eid person.id pid], pid == 'p'\n\n:pull eid {person.first_name, person.nick_name}",
"metadata": {
"trusted": true
},
"execution_count": 41,
"outputs": [
{
"execution_count": 41,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">pid</td><td style=\"font-weight: bold\">eid</td></tr></thead><tbody><tr><td>p</td><td><span style=\"color: #bf5b3d;\">{"_id":"550dad48-3501-11ed-8dc9-9aefd164fdd2","person.first_name":"Pete","person.nick_name":["Pan","Ping"]}</span></td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 2ms</span></div>"
},
"metadata": {}
}
]
},
{
"cell_type": "markdown",
"source": "Now the new nick name is simply recorded together with the last one. Note that if you try to add the same nickname for the same person again, you still get only one copy instead of two:",
"metadata": {}
},
{
"cell_type": "code",
"source": ":tx\n\n{_key: ['person.id', 'p'], person.nick_name: \"Ping\"}",
"metadata": {
"trusted": true
},
"execution_count": 37,
"outputs": [
{
"execution_count": 37,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">entity_id</td><td style=\"font-weight: bold\">asserts</td><td style=\"font-weight: bold\">retracts</td></tr></thead><tbody><tr><td>550dad48-3501-11ed-8dc9-9aefd164fdd2</td><td><span style=\"color: #307fc1;\">1</span></td><td><span style=\"color: #307fc1;\">0</span></td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 2ms</span></div>"
},
"metadata": {}
}
]
},
{
"cell_type": "code",
"source": "?[pid, eid] := [eid person.id pid]\n\n:pull eid {person.first_name, person.nick_name}",
"metadata": {
"trusted": true
},
"execution_count": 38,
"outputs": [
{
"execution_count": 38,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">pid</td><td style=\"font-weight: bold\">eid</td></tr></thead><tbody><tr><td>p</td><td><span style=\"color: #bf5b3d;\">{"_id":"550dad48-3501-11ed-8dc9-9aefd164fdd2","person.first_name":"Pete","person.nick_name":["Pan","Ping"]}</span></td></tr><tr><td>q</td><td><span style=\"color: #bf5b3d;\">{"_id":"567c963a-3501-11ed-9c95-82ccbc12f696","person.first_name":"Quin","person.nick_name":["Q","The Quick"]}</span></td></tr><tr><td>r</td><td><span style=\"color: #bf5b3d;\">{"_id":"567c9806-3501-11ed-8e7b-d4c62ea1da21","person.first_name":"Rich","person.nick_name":[]}</span></td></tr></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 3ms</span></div>"
},
"metadata": {}
}
]
},
{
"cell_type": "markdown",
"source": "As we have seen, triples abide by set semantics instead of bag semantics as well. If you really want to have duplicates, you need to disambiguate them at the level of values, by for example wrapping them in lists.",
"metadata": {}
},
{
"cell_type": "markdown",
"source": "## The time machine",
"metadata": {}
},
{
"cell_type": "code",
"source": "a[] <- [[1]]\n?[a] := a[a], a > 100\n\n:assert none",
"metadata": {
"trusted": true
},
"execution_count": 2,
"outputs": [
{
"execution_count": 2,
"output_type": "execute_result",
"data": {
"text/html": "<div style=\"display: flex; align-items: end; flex-direction: row;\"><table><thead><tr><td style=\"font-weight: bold\">a</td></tr></thead><tbody></tbody></table><span style=\"color: darkgrey; font-size: xx-small; margin: 13px;\">Took 0ms</span></div>"
},
"metadata": {}
}
]
},
{
"cell_type": "code",
"source": "",
Ziyang Hu
2 years ago