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| import neo4js, { ModelInstance } from "./index";
import { RelationType } from "./Relation";
function getRelationString(
label: string,
relationType: RelationType,
variable: string = ""
) {
return `${
!relationType.out && !relationType.any ? "<" : ""
}-[${variable}:${label}]-${
!relationType.out && !relationType.any ? "" : ">"
}`;
}
export async function get(
instance: ModelInstance<any>,
label: string,
relationType: RelationType
): Promise<any> {
const relationString = getRelationString(label, relationType);
const result = await neo4js.run(
`
MATCH (a:${this.src.label} {guid:{_srcGuid}})${relationString}(b:${
this.dest.label
})
RETURN b
`,
{ _srcGuid: instance.props.guid }
);
if (result.length === 0) {
return Promise.resolve(null);
}
Iif (result.length > 1) {
return Promise.reject("hasOne has more than one relations");
}
return Promise.resolve(this.dest._createModelInstance(result[0].b));
}
export async function create(
instance: ModelInstance<any>,
label: string,
relationType: RelationType,
props: any
): Promise<any> {
const destInstance = await this.dest.create(props);
const relationString = getRelationString(label, relationType);
const result = await neo4js.run(
`
MATCH (a:${this.src.label} {guid:{srcGuid}})${relationString}(b:${
this.dest.label
})
DETACH DELETE b
`,
{ srcGuid: instance.props.guid }
);
await neo4js.run(
`
MATCH
(a:${this.src.label} {guid:{srcGuid}}),
(b:${this.dest.label} {guid:{destGuid}})
MERGE (a)${relationString}(b)
`,
{ srcGuid: instance.props.guid, destGuid: destInstance.props.guid }
);
return Promise.resolve(destInstance);
}
export async function remove(
instance: ModelInstance<any>,
label: string,
relationType: RelationType
): Promise<any> {
const relationString = getRelationString(label, relationType, "c");
const result = await neo4js.run(
`
MATCH (a:${this.src.label} {guid:{srcGuid}})${relationString}(b:${
this.dest.label
})
DELETE c
`,
{ srcGuid: instance.props.guid }
);
return Promise.resolve(result._stats);
}
export async function add(
instance: ModelInstance<any>,
label: string,
relationType: RelationType,
destInstance: ModelInstance<any>
): Promise<boolean> {
const relationString = getRelationString(label, relationType);
const result = await neo4js.run(
`
MATCH
(a:${this.src.label} {guid:{srcGuid}}),
(b:${this.dest.label} {guid:{destGuid}})
MERGE (a)${relationString}(b)
`,
{ srcGuid: instance.props.guid, destGuid: destInstance.props.guid }
);
Eif (result._stats.relationshipsCreated === 1) {
return Promise.resolve(true);
}
return Promise.resolve(false);
}
export async function hasOne(
instance: ModelInstance<any>,
label: string,
relationType: RelationType
): Promise<boolean> {
const relationString = getRelationString(label, relationType);
const result = await neo4js.run(
`
MATCH
(a:${this.src.label} {guid:{srcGuid}})${relationString}(b:${
this.dest.label
})
RETURN b
`,
{ srcGuid: instance.props.guid }
);
if (result.length === 1) {
return Promise.resolve(true);
} else Iif (result.length > 1) {
return Promise.reject(
new Error("HasOne relation has more than one relations")
);
}
return Promise.resolve(false);
}
export async function update(
instance: ModelInstance<any>,
label: string,
relationType: RelationType,
newProps: any
): Promise<any> {
const relationString = getRelationString(label, relationType);
let props: any = await neo4js.run(
`
MATCH (a:${this.src.label} {guid:{srcGuid}})${relationString}(b:${
this.dest.label
})
RETURN b
`,
{ srcGuid: instance.props.guid }
);
if (props.length === 0) {
return Promise.resolve(true);
} else Iif (props.length > 1) {
return Promise.reject(
new Error("HasOne relation has more than one relations")
);
}
props = props[0].b;
const destInstance = await this.dest.update({ guid: props.guid }, newProps);
Eif (destInstance.length === 1) {
return Promise.resolve(destInstance[0]);
}
return Promise.reject(new Error("Problem with the update"));
}
|